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Intonti K, Faella E, Kumar A, Viscardi L, Giubileo F, Martucciello N, Lam HT, Anastasiou K, Craciun M, Russo S, Di Bartolomeo A. Temperature-Dependent Conduction and Photoresponse in Few-Layer ReS 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:50302-50311. [PMID: 37862154 PMCID: PMC10623565 DOI: 10.1021/acsami.3c12973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 10/05/2023] [Indexed: 10/22/2023]
Abstract
The electrical behavior and the photoresponse of rhenium disulfide field-effect transistors (FETs) have been widely studied; however, only a few works have investigated the photocurrent as a function of temperature. In this paper, we perform the electrical characterization of few-layer ReS2-based FETs with Cr-Au contacts over a wide temperature range. We exploit the temperature-dependent transfer and output characteristics to estimate the effective Schottky barrier at the Cr-Au/ReS2 interface and to investigate the temperature behavior of parameters, such as the threshold voltage, carrier concentration, mobility, and subthreshold swing. Through time-resolved photocurrent measurements, we show that the photocurrent increases with temperature and exhibits a linear dependence on the incident light power at both low and room temperatures and a longer rise/decay time at higher temperatures. We surmise that the photocurrent is affected by the photobolometric effect and light-induced desorption of adsorbates which are facilitated by the high temperature and the low pressure.
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Affiliation(s)
- Kimberly Intonti
- Department
of Physics “E.R. Caianiello”, University of Salerno, Fisciano 84084, Salerno, Italy
- CNR-SPIN, Fisciano 84084, Salerno, Italy
| | - Enver Faella
- Department
of Physics “E.R. Caianiello”, University of Salerno, Fisciano 84084, Salerno, Italy
- CNR-SPIN, Fisciano 84084, Salerno, Italy
| | - Arun Kumar
- Department
of Physics “E.R. Caianiello”, University of Salerno, Fisciano 84084, Salerno, Italy
- CNR-SPIN, Fisciano 84084, Salerno, Italy
| | - Loredana Viscardi
- Department
of Physics “E.R. Caianiello”, University of Salerno, Fisciano 84084, Salerno, Italy
- CNR-SPIN, Fisciano 84084, Salerno, Italy
| | | | | | - Hoi Tung Lam
- University
of Exeter, Stocker Road 6, Exeter EX4 4QL, Devon, U.K.
| | | | - Monica Craciun
- University
of Exeter, Stocker Road 6, Exeter EX4 4QL, Devon, U.K.
| | - Saverio Russo
- University
of Exeter, Stocker Road 6, Exeter EX4 4QL, Devon, U.K.
| | - Antonio Di Bartolomeo
- Department
of Physics “E.R. Caianiello”, University of Salerno, Fisciano 84084, Salerno, Italy
- CNR-SPIN, Fisciano 84084, Salerno, Italy
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52
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Kim G, Dang DX, Gul HZ, Ji H, Kim EK, Lim SC. Investigating charge traps in MoTe 2field-effect transistors: SiO 2insulator traps and MoTe 2bulk traps. NANOTECHNOLOGY 2023; 35:035702. [PMID: 37804823 DOI: 10.1088/1361-6528/ad0126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 10/06/2023] [Indexed: 10/09/2023]
Abstract
Two-dimensional material-based field-effect transistors are promising for future use in electronic and optoelectronic applications. However, trap states existing in the transistors are known to hinder device performance. They capture/release carriers in the channel and lead to hysteresis in the transfer characteristics. In this work, we fabricated MoTe2field-effect transistors on two different gate dielectrics, SiO2and h-BN, and investigated temperature-dependent charge trapping behavior on the hysteresis in their transfer curves. We observed that devices with SiO2back-gate dielectric are affected by both SiO2insulator traps and MoTe2intrinsic bulk traps, with the latter becoming prominent at temperatures above 310 K. Conversely, devices with h-BN back-gate dielectric, which host a negligible number of insulator traps, primarily exhibit MoTe2bulk traps at high temperatures, enabling us to estimate the trap energy level at 389 meV below the conduction band edge. A similar energy level of 396 meV below the conduction band edge was observed from the emission current transient measurement. From a previous computational study, we expect these trap states to be the tellurium vacancy. Our results suggest that charge traps in MoTe2field-effect transistors can be reduced by careful selection of gate insulators, thus providing guidelines for device fabrication.
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Affiliation(s)
- Giheon Kim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Dang Xuan Dang
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hamza Zad Gul
- Department of Electrical Engineering, Namal University, Mianwali 42250, Pakistan
| | - Hyunjin Ji
- Department of Electrical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Eun Kyu Kim
- Department of Physics and Quantum-Function Research Laboratory, Hanyang University, Seoul 04763, Republic of Korea
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fabrication Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
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53
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Wang X, Hu Y, Kim SY, Addou R, Cho K, Wallace RM. Origins of Fermi Level Pinning for Ni and Ag Metal Contacts on Tungsten Dichalcogenides. ACS NANO 2023; 17:20353-20365. [PMID: 37788682 DOI: 10.1021/acsnano.3c06494] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Tungsten transition metal dichalcogenides (W-TMDs) are intriguing due to their properties and potential for application in next-generation electronic devices. However, strong Fermi level (EF) pinning manifests at the metal/W-TMD interfaces, which could tremendously restrain the carrier injection into the channel. In this work, we illustrate the origins of EF pinning for Ni and Ag contacts on W-TMDs by considering interface chemistry, band alignment, impurities, and imperfections of W-TMDs, contact metal adsorption mechanism, and the resultant electronic structure. We conclude that the origins of EF pinning at a covalent contact metal/W-TMD interface, such as Ni/W-TMDs, can be attributed to defects, impurities, and interface reaction products. In contrast, for a van der Waals contact metal/TMD system such as Ag/W-TMDs, the primary factor responsible for EF pinning is the electronic modification of the TMDs resulting from the defects and impurities with the minor impact of metal-induced gap states. The potential strategies for carefully engineering the metal deposition approach are also discussed. This work unveils the origins of EF pinning at metal/TMD interfaces experimentally and theoretically and provides guidance on further enhancing and improving the device performance.
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Affiliation(s)
- Xinglu Wang
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Yaoqiao Hu
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Seong Yeoul Kim
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Rafik Addou
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Kyeongjae Cho
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Robert M Wallace
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, Texas 75080, United States
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54
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Ahn B, Kim Y, Kim M, Yu HM, Ahn J, Sim E, Ji H, Gul HZ, Kim KS, Ihm K, Lee H, Kim EK, Lim SC. One-Step Passivation of Both Sulfur Vacancies and SiO 2 Interface Traps of MoS 2 Device. NANO LETTERS 2023; 23:7927-7933. [PMID: 37647420 DOI: 10.1021/acs.nanolett.3c01753] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Transition metal dichalcogenides (TMDs) benefit electrical devices with spin-orbit coupling and valley- and topology-related properties. However, TMD-based devices suffer from traps arising from defect sites inside the channel and the gate oxide interface. Deactivating them requires independent treatments, because the origins are dissimilar. This study introduces a single treatment to passivate defects in a multilayer MoS2 FET. By applying back-gate bias, protons from an H-TFSI droplet are injected into the MoS2, penetrating deeply enough to reach the SiO2 gate oxide. The characterizations employing low-temperature transport and deep-level transient spectroscopy (DLTS) studies reveal that the trap density of S vacancies in MoS2 drops to the lowest detection level. The temperature-dependent mobility plot on the SiO2 substrate resembles that of the h-BN substrate, implying that dangling bonds in SiO2 are passivated. The carrier mobility on the SiO2 substrate is enhanced by approximately 2200% after the injection.
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Affiliation(s)
- Byungwook Ahn
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yoonsok Kim
- Department of Physics, Hanyang University, Seoul 04763, Republic of Korea
- Institute of Plasma Technology, Korea Institute of Fusion Energy, Gunsan 54004, Republic of Korea
| | - Meeree Kim
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyang Mi Yu
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jaehun Ahn
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eunji Sim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyunjin Ji
- Department of Electrical Engineering, University of Ulsan, Ulsan 44610, Republic of Korea
| | - Hamza Zad Gul
- Department of Electrical Engineering, Namal University, 30 km Talagang Road, Mianwali 42250, Pakistan
| | - Keun Soo Kim
- Department of Physics and Graphene Research Institute, Sejong University, Seoul 05006, Republic of Korea
| | - Kyuwook Ihm
- Nano & Interface Research Team, Pohang Accelerator Laboratory, Pohang 37673, Republic of Korea
| | - Hyoyoung Lee
- Department of Chemistry, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Eun Kyu Kim
- Department of Physics, Hanyang University, Seoul 04763, Republic of Korea
| | - Seong Chu Lim
- Department of Energy Science, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Smart Fabrication Technology, Sungkyunkwan University, Suwon 16419, Republic of Korea
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55
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Lee B, Jeong BJ, Choi KH, Cho S, Jeon J, Kang J, Zhang X, Bang HS, Oh HS, Lee JH, Yu HK, Choi JY. Fabrication of a Field-Effect Transistor Based on 2D Novel Ternary Chalcogenide PdPS. ACS APPLIED MATERIALS & INTERFACES 2023; 15:42891-42899. [PMID: 37657071 DOI: 10.1021/acsami.3c09679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/03/2023]
Abstract
Two-dimensional (2D) palladium phosphide sulfide (PdPS) has garnered significant attention, owing to its exotic physical properties originating from the distinct Cairo pentagonal tiling topology. Nevertheless, the properties of PdPS remain unexplored, especially for electronic devices. In this study, we introduce the thickness-dependent electrical characteristics of PdPS flakes into fabricated field-effect transistors (FETs). The broad thickness variation of the PdPS flakes, ranging from 0.7-306 nm, is prepared by mechanical exfoliation, utilizing large bulk crystals synthesized via chemical vapor transport. We evaluate this variation and confirm a high electron mobility of 14.4 cm2 V-1 s-1 and Ion/Ioff > 107. Furthermore, the 6.8 nm-thick PdPS FET demonstrates a negligible Schottky barrier height at the gold electrode contact, as evidenced by the measurement of the temperature-dependent transfer characteristics. Consequently, we adjusted the Fowler-Nordheim tunneling mechanism to elucidate the charge-transport mechanism, revealing a modulated mobility variation from 14.4 to 41.2 cm2 V-1 s-1 with an increase in the drain voltage from 1 to 5 V. The present findings can broaden the understanding of the unique properties of PdPS, highlighting its potential as a 2D ternary chalcogenide in future electronic device applications.
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Affiliation(s)
- Bom Lee
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Byung Joo Jeong
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Kyung Hwan Choi
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sooheon Cho
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jiho Jeon
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jinsu Kang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Xiaojie Zhang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hyeon-Seok Bang
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Hyung-Suk Oh
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
- KIST-SKKU Carbon-Neutral Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jae-Hyun Lee
- Department of Materials Science and Engineering & Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Hak Ki Yu
- Department of Materials Science and Engineering & Department of Energy Systems Research, Ajou University, Suwon 16499, Republic of Korea
| | - Jae-Young Choi
- School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea
- SKKU Advanced Institute of Nanotechnology (SAINT), Sungkyunkwan University, Suwon 16419, Republic of Korea
- KIST-SKKU Carbon-Neutral Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
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56
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Yao YC, Wu BY, Chin HT, Yen ZL, Ting CC, Hofmann M, Hsieh YP. Nitrogen Pretreatment of Growth Substrates for Vacancy-Saturated MoS 2. ACS APPLIED MATERIALS & INTERFACES 2023; 15:42746-42752. [PMID: 37646637 DOI: 10.1021/acsami.3c07793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Two-dimensional transition-metal dichalcogenides (2D TMDCs) are considered promising materials for optoelectronics due to their unique optical and electric properties. However, their potential has been limited by the occurrence of atomic vacancies during synthesis. While post-treatment processes have demonstrated the passivation of such vacancies, they increase process complexity and affect the TMDC's quality. We here introduce the concept of pretreatment as a facile and powerful route to solve the problem of vacancies in MoS2. Low-temperature nitridation of the sapphire substrate prior to growth provides a nondestructive method to MoS2 modification without introducing new processing steps or increasing the thermal budget. Spectroscopic characterization and atomic-resolution microscopy reveal the incorporation of nitrogen from the sapphire surface layer into chalcogen vacancies. The resulting MoS2 with nitrogen-saturated defects shows a decrease in midgap states and more intrinsic doping as confirmed by ab initio calculations and optoelectronic measurements. The demonstrated pretreatment method opens up new routes toward future, high-performance 2D electronics, as evidenced by a 3-fold reduction in contact resistance and a 10-fold improved performance of 2D photodetectors.
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Affiliation(s)
- Yu-Chi Yao
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Bo-Yi Wu
- Graduate Institute of Opto-Mechatronics, Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 62102, Taiwan
| | - Hao-Ting Chin
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei 10617, Taiwan
- Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 10617, Taiwan
| | - Zhi-Long Yen
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
- International Graduate Program of Molecular Science and Technology, National Taiwan University, Taipei 10617, Taiwan
- Molecular Science and Technology Program, Taiwan International Graduate Program, Academia Sinica, Taipei 10617, Taiwan
| | - Chu-Chi Ting
- Graduate Institute of Opto-Mechatronics, Department of Mechanical Engineering, National Chung Cheng University, Chia-Yi 62102, Taiwan
| | - Mario Hofmann
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Ya-Ping Hsieh
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
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57
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Ma L, Tao Q, Chen Y, Lu Z, Liu L, Li Z, Lu D, Wang Y, Liao L, Liu Y. Realizing On/Off Ratios over 10 4 for Sub-2 nm Vertical Transistors. NANO LETTERS 2023; 23:8303-8309. [PMID: 37646535 DOI: 10.1021/acs.nanolett.3c02518] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Vertical transistors hold promise for the development of ultrascaled transistors. However, their on/off ratios are limited by a strong source-drain tunneling current in the off state, particularly for vertical devices with a sub-5 nm channel length. Here, we report an approach for suppressing the off-state tunneling current by designing the barrier height via a van der Waals metal contact. Via lamination of the Pt electrode on a MoS2 vertical transistor, a high Schottky barrier is observed due to their large work function difference, thus suppressing direct tunneling currents. Meanwhile, this "low-energy" lamination process ensures an optimized metal/MoS2 interface with minimized interface states and defects. Together, the highest on/off ratios of 5 × 105 and 104 are realized in vertical transistors with 5 and 2 nm channel lengths, respectively. Our work not only pushes the on/off ratio limit of vertical transistors but also provides a general rule for reducing short-channel effects in ultrascaled devices.
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Affiliation(s)
- Likuan Ma
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Quanyang Tao
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yang Chen
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Zheyi Lu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Liting Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Zhiwei Li
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Donglin Lu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yiliu Wang
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Lei Liao
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Yuan Liu
- Key Laboratory for Micro-Nano Optoelectronic Devices of Ministry of Education, School of Physics and Electronics, Hunan University, Changsha 410082, China
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58
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Mahlouji R, Kessels WMME, Sagade AA, Bol AA. ALD-grown two-dimensional TiS x metal contacts for MoS 2 field-effect transistors. NANOSCALE ADVANCES 2023; 5:4718-4727. [PMID: 37705798 PMCID: PMC10496909 DOI: 10.1039/d3na00387f] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 07/13/2023] [Indexed: 09/15/2023]
Abstract
Metal contacts to MoS2 field-effect transistors (FETs) play a determinant role in the device electrical characteristics and need to be chosen carefully. Because of the Schottky barrier (SB) and the Fermi level pinning (FLP) effects that occur at the contact/MoS2 interface, MoS2 FETs often suffer from high contact resistance (Rc). One way to overcome this issue is to replace the conventional 3D bulk metal contacts with 2D counterparts. Herein, we investigate 2D metallic TiSx (x ∼ 1.8) as top contacts for MoS2 FETs. We employ atomic layer deposition (ALD) for the synthesis of both the MoS2 channels as well as the TiSx contacts and assess the electrical performance of the fabricated devices. Various thicknesses of TiSx are grown on MoS2, and the resultant devices are electrically compared to the ones with the conventional Ti metal contacts. Our findings show that the replacement of 5 nm Ti bulk contacts with only ∼1.2 nm of 2D TiSx is beneficial in improving the overall device metrics. With such ultrathin TiSx contacts, the ON-state current (ION) triples and increases to ∼35 μA μm-1. Rc also reduces by a factor of four and reaches ∼5 MΩ μm. Such performance enhancements were observed despite the SB formed at the TiSx/MoS2 interface is believed to be higher than the SB formed at the Ti/MoS2 interface. These device metric improvements could therefore be mainly associated with an increased level of electrostatic doping in MoS2, as a result of using 2D TiSx for contacting the 2D MoS2. Our findings are also well supported by TCAD device simulations.
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Affiliation(s)
- Reyhaneh Mahlouji
- Department of Applied Physics, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
| | - Wilhelmus M M Erwin Kessels
- Department of Applied Physics, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
| | - Abhay A Sagade
- Department of Physics and Nanotechnology, Laboratory for Advanced Nanoelectronic Devices, SRM Institute of Science and Technology SRM Nagar, Kattankulathur 603 203 Tamil Nadu India
| | - Ageeth A Bol
- Department of Applied Physics, Eindhoven University of Technology P. O. Box 513 5600 MB Eindhoven The Netherlands
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Mondal A, Biswas C, Park S, Cha W, Kang SH, Yoon M, Choi SH, Kim KK, Lee YH. Low Ohmic contact resistance and high on/off ratio in transition metal dichalcogenides field-effect transistors via residue-free transfer. NATURE NANOTECHNOLOGY 2023:10.1038/s41565-023-01497-x. [PMID: 37666942 DOI: 10.1038/s41565-023-01497-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 08/01/2023] [Indexed: 09/06/2023]
Abstract
Beyond-silicon technology demands ultrahigh performance field-effect transistors. Transition metal dichalcogenides provide an ideal material platform, but the device performances such as the contact resistance, on/off ratio and mobility are often limited by the presence of interfacial residues caused by transfer procedures. Here, we show an ideal residue-free transfer approach using polypropylene carbonate with a negligible residue coverage of ~0.08% for monolayer MoS2 at the centimetre scale. By incorporating a bismuth semimetal contact with an atomically clean monolayer MoS2 field-effect transistor on hexagonal boron nitride substrate, we obtain an ultralow Ohmic contact resistance of ~78 Ω µm, approaching the quantum limit, and a record-high on/off ratio of ~1011 at 15 K. Such an ultra-clean fabrication approach could be the ideal platform for high-performance electrical devices using large-area semiconducting transition metal dichalcogenides.
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Affiliation(s)
- Ashok Mondal
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea
| | - Chandan Biswas
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Sehwan Park
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea
| | - Wujoon Cha
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea
| | - Seoung-Hun Kang
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Mina Yoon
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Soo Ho Choi
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea
| | - Ki Kang Kim
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea
- Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea
| | - Young Hee Lee
- Center for Integrated Nanostructure Physics, Institute for Basic Science, Sungkyunkwan University, Suwon, Republic of Korea.
- Department of Energy Science, Sungkyunkwan University, Suwon, Republic of Korea.
- Department of Physics, Sungkyunkwan University, Suwon, Republic of Korea.
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60
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Kwon G, Kim HS, Jeong K, Kim M, Nam GH, Park H, Yoo K, Cho MH. Forming Stable van der Waals Contacts between Metals and 2D Semiconductors. SMALL METHODS 2023; 7:e2300376. [PMID: 37291738 DOI: 10.1002/smtd.202300376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/19/2023] [Indexed: 06/10/2023]
Abstract
High-performing 2D electrical and optical devices can be realized by forming an ideal van der Waals (vdW) metal contact with weak interactions and stable interface states. However, the methods for applying metal contacts while avoiding damage from metal deposition present challenges in realizing a uniform, stable vdW interface. To overcome this problem, this study develops a method for forming vdW contacts using a sacrificial Se buffer layer. This study explores this method by investigating the difference in the Schottky barrier height between the vdW metal contact deposited using a buffer layer, a transferred metal contact, and a conventional directly deposited metal contact using rectification and photovoltaic characteristics of a Schottky diode structure with graphite. Evidently, the Se buffer layer method forms the most stable and ideal vdW contact while preventing Fermi-level pinning. A tungsten diselenide Schottky diode fabricated using these vdW contacts with Au and graphite as the top and bottom electrodes, respectively, exhibits excellent operation with an ideality factor of ≈1, an on/off ratio of > 107 , and coherent properties. Additionally, when using only the vdW Au contact, the electrical and optical properties of the device can be minutely modulated by changing the structure of the Schottky diode.
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Affiliation(s)
- Gihyeon Kwon
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hyeon-Sik Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kwangsik Jeong
- Division of Physics and Semiconductor Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Myeongjin Kim
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Gi Hwan Nam
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Hyunjun Park
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Kyunghwa Yoo
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
| | - Mann-Ho Cho
- Department of Physics, Yonsei University, Seoul, 03722, Republic of Korea
- Department of System Semiconductor Engineering, Yonsei University, Seoul, 03722, Republic of Korea
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Qi L, Che M, Liu M, Wang B, Zhang N, Zou Y, Sun X, Shi Z, Li D, Li S. Mechanistic understanding of the interfacial properties of metal-PtSe 2 contacts. NANOSCALE 2023; 15:13252-13261. [PMID: 37548442 DOI: 10.1039/d3nr02466k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
With the advantages of a moderate band gap, high carrier mobility and good environmental stability, two-dimensional (2D) semiconductors show promising applications in next-generation electronics. However, the accustomed metal-2D semiconductor contact may lead to a strong Fermi level pinning (FLP) effect, which severely limits the practical performance of 2D electronics. Herein, the interfacial properties of the contacts between a promising 2D semiconductor, PtSe2, and a sequence of metal electrodes are systematically investigated. The strong interfacial interactions formed in all metal-PtSe2 contacts lead to chemical bonds and a significant interfacial dipole, resulting in a vertical Schottky barrier for Ag, Au, Pd and Pt-based systems and a lateral Schottky barrier for Al, Cu, Sc and Ti-based systems, with a strong FLP effect. Remarkably, the tunneling probability for most metal-PtSe2 is significantly high and the tunneling-specific resistivity is two orders of magnitude lower than that of the state-of-the-art contacts, demonstrating the high efficiency for electron injection from metals to PtSe2. Moreover, the introduction of h-BN as a buffer layer leads to a weakened FLP effect (S = 0.50) and the transformation into p-type Schottky contact for Pt-PtSe2 contacts. These results reveal the underlying mechanism of the interfacial properties of metal-PtSe2 contacts, which is useful for designing advanced 2D semiconductor-based electronics.
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Affiliation(s)
- Liujian Qi
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Mengqi Che
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Mingxiu Liu
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Bin Wang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Nan Zhang
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Yuting Zou
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Xiaojuan Sun
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Zhiming Shi
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Dabing Li
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
| | - Shaojuan Li
- State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Science, Changchun, Jilin 130033, P. R. China.
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Song S, Yoon A, Jang S, Lynch J, Yang J, Han J, Choe M, Jin YH, Chen CY, Cheon Y, Kwak J, Jeong C, Cheong H, Jariwala D, Lee Z, Kwon SY. Fabrication of p-type 2D single-crystalline transistor arrays with Fermi-level-tuned van der Waals semimetal electrodes. Nat Commun 2023; 14:4747. [PMID: 37550303 PMCID: PMC10406929 DOI: 10.1038/s41467-023-40448-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Accepted: 07/26/2023] [Indexed: 08/09/2023] Open
Abstract
High-performance p-type two-dimensional (2D) transistors are fundamental for 2D nanoelectronics. However, the lack of a reliable method for creating high-quality, large-scale p-type 2D semiconductors and a suitable metallization process represents important challenges that need to be addressed for future developments of the field. Here, we report the fabrication of scalable p-type 2D single-crystalline 2H-MoTe2 transistor arrays with Fermi-level-tuned 1T'-phase semimetal contact electrodes. By transforming polycrystalline 1T'-MoTe2 to 2H polymorph via abnormal grain growth, we fabricated 4-inch 2H-MoTe2 wafers with ultra-large single-crystalline domains and spatially-controlled single-crystalline arrays at a low temperature (~500 °C). Furthermore, we demonstrate on-chip transistors by lithographic patterning and layer-by-layer integration of 1T' semimetals and 2H semiconductors. Work function modulation of 1T'-MoTe2 electrodes was achieved by depositing 3D metal (Au) pads, resulting in minimal contact resistance (~0.7 kΩ·μm) and near-zero Schottky barrier height (~14 meV) of the junction interface, and leading to high on-state current (~7.8 μA/μm) and on/off current ratio (~105) in the 2H-MoTe2 transistors.
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Affiliation(s)
- Seunguk Song
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Aram Yoon
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Sora Jang
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jason Lynch
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Jihoon Yang
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Juwon Han
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Myeonggi Choe
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Young Ho Jin
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Cindy Yueli Chen
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Yeryun Cheon
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Jinsung Kwak
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
- Department of Physics, Changwon National University, Changwon, 51140, Republic of Korea
| | - Changwook Jeong
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyeonsik Cheong
- Department of Physics, Sogang University, Seoul, 04107, Republic of Korea
| | - Deep Jariwala
- Department of Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, US
| | - Zonghoon Lee
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
- Center for Multidimensional Carbon Materials (CMCM), Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea.
| | - Soon-Yong Kwon
- Department of Materials Science and Engineering & Graduate School of Semiconductor Materials and Devices Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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63
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Su ZC, Lin CF. Overcoming the Fermi-Level Pinning Effect in the Nanoscale Metal and Silicon Interface. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2193. [PMID: 37570511 PMCID: PMC10420943 DOI: 10.3390/nano13152193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 07/17/2023] [Accepted: 07/26/2023] [Indexed: 08/13/2023]
Abstract
Silicon-based photodetectors are attractive as low-cost and environmentally friendly optical sensors. Also, their compatibility with complementary metal-oxide-semiconductor (CMOS) technology is advantageous for the development of silicon photonics systems. However, extending optical responsivity of silicon-based photodetectors to the mid-infrared (mid-IR) wavelength range remains challenging. In developing mid-IR infrared Schottky detectors, nanoscale metals are critical. Nonetheless, one key factor is the Fermi-level pinning effect at the metal/silicon interface and the presence of metal-induced gap states (MIGS). Here, we demonstrate the utilization of the passivated surface layer on semiconductor materials as an insulating material in metal-insulator-semiconductor (MIS) contacts to mitigate the Fermi-level pinning effect. The removal of Fermi-level pinning effectively reduces the Schottky barrier height by 12.5% to 16%. The demonstrated devices exhibit a high responsivity of up to 234 μA/W at a wavelength of 2 μm, 48.2 μA/W at 3 μm, and 1.75 μA/W at 6 μm. The corresponding detectivities at 2 and 3 μm are 1.17 × 108 cm Hz1/2 W-1 and 2.41 × 107 cm Hz1/2 W-1, respectively. The expanded sensing wavelength range contributes to the application development of future silicon photonics integration platforms.
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Affiliation(s)
- Zih-Chun Su
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan;
| | - Ching-Fuh Lin
- Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei 10617, Taiwan;
- Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 10617, Taiwan
- Department of Electrical Engineering, National Taiwan University, Taipei 10617, Taiwan
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64
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Xu L, Zhan G, Luo K, Lu F, Zhang S, Wu Z. Transition from Schottky to ohmic contacts in the C 31 and MoS 2 van der Waals heterostructure. Phys Chem Chem Phys 2023; 25:20128-20133. [PMID: 37462991 DOI: 10.1039/d3cp02357e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
The utilization of conventional metal contacts has restricted the industrial implementation of two-dimensional channel materials. To address this issue, we conducted first-principles calculations to investigate the interface properties of C31 and MoS2 contacts. An ohmic contact and a low van der Waals barrier were found in the C31/MoS2 heterostructure. Our findings provide a promising new contact metal material for two-dimensional nanodevices based on MoS2.
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Affiliation(s)
- Lijun Xu
- The Key Laboratory of Microelectronics Device and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing 100029, China
| | - Guohui Zhan
- The Key Laboratory of Microelectronics Device and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing 100029, China
| | - Kun Luo
- The Key Laboratory of Microelectronics Device and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing 100029, China
| | - Fei Lu
- School of Integrated Circuits, Southeast University, Nanjing 210094, China
| | - Shengli Zhang
- MIIT Key Laboratory of Advanced Display Materials and Devices, College of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Zhenhua Wu
- The Key Laboratory of Microelectronics Device and Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- School of Integrated Circuits, University of Chinese Academy of Sciences, Beijing 100029, China
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65
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Fu Y, Zhu J, Sun Y, Sun S, Tie K, Qi J, Wang Y, Wang Z, Hu Y, Ding S, Huang R, Gong Z, Huang Y, Chen X, Li L, Hu W. Oxygen-Induced Barrier Lowering for High-Performance Organic Field-Effect Transistors. ACS NANO 2023. [PMID: 37487031 DOI: 10.1021/acsnano.3c04177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Organic field-effect transistors (OFETs) have the advantages of low-cost, large-area processing and could be utilized in a variety of emerging applications. However, the generally large contact resistance (Rc) limits the integration and miniaturization of OFETs. The Rc is difficult to reduce due to an incompatibility between obtaining strong orbit coupling and the barrier height reduction. In this study, we developed an oxygen-induced barrier lowering strategy by introducing oxygen (O2) into the nanointerface between the electrodes and organic semiconductors layer and achieved an ultralow channel width-normalized Rc (Rc·W) of 89.8 Ω·cm and a high mobility of 11.32 cm2 V-1 s-1. This work demonstrates that O2 adsorbed at the nanointerface of metal-semiconductor contact can significantly reduce the Rc from both experiments and theoretical simulations and provides guidance for the construction of high-performance OFETs, which is conducive to the integration and miniaturization of OFETs.
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Affiliation(s)
- Yao Fu
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Jie Zhu
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Yajing Sun
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Shougang Sun
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Kai Tie
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Jiannan Qi
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Yanpeng Wang
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Zhongwu Wang
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Yongxu Hu
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Shuaishuai Ding
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Rong Huang
- Vacuum Interconnected Nanotech Workstation (NANO-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215125, China
| | - Zhongmiao Gong
- Vacuum Interconnected Nanotech Workstation (NANO-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences, Suzhou 215125, China
| | - Yinan Huang
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Xiaosong Chen
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
| | - Liqiang Li
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou 350207, China
| | - Wenping Hu
- Key Laboratory of Organic Integrated Circuits, Ministry of Education, Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, China
- Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Fuzhou 350207, China
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66
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Wang X, Yu S, Xu Y, Huang B, Dai Y, Wei W. Ohmic contacts of the two-dimensional Ca 2N/MoS 2 donor-acceptor heterostructure. Phys Chem Chem Phys 2023. [PMID: 37254579 DOI: 10.1039/d3cp01412f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In the current stage, conventional silicon-based devices are suffering from the scaling limits and the Fermi level pinning effect. Therefore, looking for low-resistance metal contacts for semiconductors has become one of the most important topics, and two-dimensional (2D) metal/semiconductor contacts turn out to be highly interesting. Alternatively, the Schottky barrier and the tunneling barrier impede their practical applications. In this work, we propose a new strategy for reducing the contact potential barrier by constructing a donor-acceptor heterostructure, that is, Ca2N/MoS2 with Ca2N being a 2D electrene material with a significantly small work function and a rather high carrier concentration. The quasi-bond interaction of the heterostructure avoids the formation of a Fermi level pinning effect and gives rise to high tunneling probability. An excellent n-type Ohmic contact form between Ca2N and MoS2 monolayers, with a 100% tunneling probability and a perfect linear I-V curve, and large lateral band bending also demonstrates the good performance of the contact. We verify a fascinating phenomenon that Ca2N can trigger the phase transition of MoS2 from 2H to 1T'. In addition, we also identify that Ohmic contacts can be formed between Ca2N and other 2D transition metal dichalcogenides (TMDCs), including WS2, MoSe2, WSe2, and MoTe2.
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Affiliation(s)
- Xinxin Wang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Shiqiang Yu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Yushuo Xu
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
| | - Wei Wei
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
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Ngo TD, Huynh T, Jung H, Ali F, Jeon J, Choi MS, Yoo WJ. Modulation of Contact Resistance of Dual-Gated MoS 2 FETs Using Fermi-Level Pinning-Free Antimony Semi-Metal Contacts. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023:e2301400. [PMID: 37144526 PMCID: PMC10375162 DOI: 10.1002/advs.202301400] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Revised: 04/23/2023] [Indexed: 05/06/2023]
Abstract
Achieving low contact resistance (RC ) is one of the major challenges in producing 2D FETs for future CMOS technology applications. In this work, the electrical characteristics for semimetal (Sb) and normal metal (Ti) contacted MoS2 devices are systematically analyzed as a function of top and bottom gate-voltages (VTG and VBG ). The semimetal contacts not only significantly reduce RC but also induce a strong dependence of RC on VTG , in sharp contrast to Ti contacts that only modulate RC by varying VBG . The anomalous behavior is attributed to the strongly modulated pseudo-junction resistance (Rjun ) by VTG , resulting from weak Fermi level pinning (FLP) of Sb contacts. In contrast, the resistances under both metallic contacts remain unchanged by VTG as metal screens the electric field from the applied VTG . Technology computer aided design simulations further confirm the contribution of VTG to Rjun , which improves overall RC of Sb-contacted MoS2 devices. Consequently, the Sb contact has a distinctive merit in dual-gated (DG) device structure, as it greatly reduces RC and enables effective gate control by both VBG and VTG . The results offer new insight into the development of DG 2D FETs with enhanced contact properties realized by using semimetals.
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Affiliation(s)
- Tien Dat Ngo
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Tuyen Huynh
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, Gyeonggi-do, 16419, Republic of Korea
| | - Hanggyo Jung
- Department of Electrical and Electronics Engineering, Konkuk University, Seoul, 05029, Republic of Korea
| | - Fida Ali
- Department of Electronics and Nanoengineering, Aalto University, P.O. Box 13500, Espoo, FI-00076, Finland
| | - Jongwook Jeon
- Department of Electrical and Electronics Engineering, Konkuk University, Seoul, 05029, Republic of Korea
| | - Min Sup Choi
- Department of Materials Science and Engineering, Chungnam National University, Daejeon, 34134, Republic of Korea
| | - Won Jong Yoo
- SKKU Advanced Institute of Nano Technology, Sungkyunkwan University, Suwon, Gyeonggi-do, 16419, Republic of Korea
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68
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Wu Y, Xin Z, Zhang Z, Wang B, Peng R, Wang E, Shi R, Liu Y, Guo J, Liu K, Liu K. All-Transfer Electrode Interface Engineering Toward Harsh-Environment-Resistant MoS 2 Field-Effect Transistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210735. [PMID: 36652589 DOI: 10.1002/adma.202210735] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Revised: 01/08/2023] [Indexed: 05/05/2023]
Abstract
Nanoscale electronic devices that can work in harsh environments are in high demand for wearable, automotive, and aerospace electronics. Clean and defect-free interfaces are of vital importance for building nanoscale harsh-environment-resistant devices. However, current nanoscale devices are subject to failure in these environments, especially at defective electrode-channel interfaces. Here, harsh-environment-resistant MoS2 transistors are developed by engineering electrode-channel interfaces with an all-transfer of van der Waals electrodes. The delivered defect-free, graphene-buffered electrodes keep the electrode-channel interfaces intact and robust. As a result, the as-fabricated MoS2 devices have reduced Schottky barrier heights, leading to a very large on-state current and high carrier mobility. More importantly, the defect-free, hydrophobic graphene buffer layer prevents metal diffusion from the electrodes to MoS2 and the intercalation of water molecules at the electrode-MoS2 interfaces. This enables high resistances of MoS2 devices with all-transfer electrodes to various harsh environments, including humid, oxidizing, and high-temperature environments, surpassing the devices with other kinds of electrodes. The work deepens the understanding of the roles of electrode-channel interfaces in nanoscale devices and provides a promising interface engineering strategy to build nanoscale harsh-environment-resistant devices.
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Affiliation(s)
- Yonghuang Wu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Zeqin Xin
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Zhibin Zhang
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Bolun Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Ruixuan Peng
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Enze Wang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Run Shi
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Yiqun Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Jing Guo
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Kaihui Liu
- State Key Laboratory for Mesoscopic Physics, Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing, 100871, China
| | - Kai Liu
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
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69
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Cheng Z, Backman J, Zhang H, Abuzaid H, Li G, Yu Y, Cao L, Davydov AV, Luisier M, Richter CA, Franklin AD. Distinct Contact Scaling Effects in MoS 2 Transistors Revealed with Asymmetrical Contact Measurements. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2210916. [PMID: 36848627 DOI: 10.1002/adma.202210916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 02/15/2023] [Indexed: 05/26/2023]
Abstract
2D semiconducting materials have immense potential for future electronics due to their atomically thin nature, which enables better scalability. While the channel scalability of 2D materials has been extensively studied, the current understanding of contact scaling in 2D devices is inconsistent and oversimplified. Here physically scaled contacts and asymmetrical contact measurements (ACMs) are combined to investigate the contact scaling behavior in 2D field-effect transistors. The ACMs directly compare electron injection at different contact lengths while using the exact same MoS2 channel, eliminating channel-to-channel variations. The results show that scaled source contacts can limit the drain current, whereas scaled drain contacts do not. Compared to devices with long contact lengths, devices with short contact lengths (scaled contacts) exhibit larger variations, 15% lower drain currents at high drain-source voltages, and a higher chance of early saturation and negative differential resistance. Quantum transport simulations reveal that the transfer length of Ni-MoS2 contacts can be as short as 5 nm. Furthermore, it is clearly identified that the actual transfer length depends on the quality of the metal-2D interface. The ACMs demonstrated here will enable further understanding of contact scaling behavior at various interfaces.
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Affiliation(s)
- Zhihui Cheng
- Department of Electrical & Computer Engineering, Duke University, Durham, NC, 27708, USA
- Department of Electrical & Computer Engineering, Purdue University, West Lafayette, IN, 47907, USA
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Jonathan Backman
- Integrated Systems Laboratory, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Huairuo Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
- Theiss Research, Inc., La Jolla, California, 92037, USA
| | - Hattan Abuzaid
- Department of Electrical & Computer Engineering, Duke University, Durham, NC, 27708, USA
| | - Guoqing Li
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Yifei Yu
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Linyou Cao
- Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC, 27695, USA
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Mathieu Luisier
- Integrated Systems Laboratory, ETH Zurich, Zurich, CH-8092, Switzerland
| | - Curt A Richter
- Nanoscale Device Characterization Division, National Institute of Standards and Technology, Gaithersburg, MD, 20899, USA
| | - Aaron D Franklin
- Department of Electrical & Computer Engineering, Duke University, Durham, NC, 27708, USA
- Department of Chemistry, Duke University, Durham, NC, 27708, USA
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70
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Zhang D. DFT Simulation of a Gold Electrode Vapor-Deposition Growth Process and the Effect of Defects on the Electrode Work Function. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5649-5654. [PMID: 37052629 DOI: 10.1021/acs.langmuir.2c02710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
While two-dimensional (2D) semiconductors are explored as field-effect transistor (FET) channel materials for decreasing the short channel effects, electrical contact with 2D semiconductors is a major issue. Many efforts have been made toward this issue. However, the discrepancy in the contact type and the Schottky barrier height from the same contact is present in experiments. This discrepancy supposedly should be associated with the vapor-deposition electrode structures, on which little attention had been focused. Here, the crystal growth of the gold vapor-deposition electrode is simulated by adding gold atoms to the gold substrate one by one in the framework of density functional theory, and for every step, the spontaneously searching adsorption site method is used to find thermodynamically stable adsorption sites and the climbing nudged elastic band method is used to find kinetically stable ones. Simulation shows that the Au(111) face grows according to the ABC sequence packing, and possible defects are interstitial, vacancy, and the partly filled nascent layer (PFNL). These defects have an unequal effect on the electrode work function. The PFNL may be a non-negligible factor responsible for the discrepancy.
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Affiliation(s)
- Daoyu Zhang
- School of Physics, Southeast University, Nanjing 211189, China
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71
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Hu W, Wang H, Dong J, Sun H, Wang Y, Sheng Z, Zhang Z. Chemical Dopant-Free Controlled MoTe 2/MoSe 2 Heterostructure toward a Self-Driven Photodetector and Complementary Logic Circuits. ACS APPLIED MATERIALS & INTERFACES 2023; 15:18182-18190. [PMID: 36987733 DOI: 10.1021/acsami.2c21785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Two-dimensional (2D) van der Waals heterostructures based on transition metal dichalcogenides are expected to be unique building blocks for next-generation nanoscale electronics and optoelectronics. The ability to control the properties of 2D heterostructures is the key for practical applications. Here, we report a simple way to fabricate a high-performance self-driven photodetector based on the MoTe2/MoSe2 p-n heterojunction, in which the hole-dominated transport polarity of MoTe2 is easily achieved via a straightforward thermal annealing treatment in air without any chemical dopants or special gases needed. A high photoresponsivity of 0.72 A W-1, an external quantum efficiency up to 41.3%, a detectivity of 7 × 1011 Jones, and a response speed of 120 μs are obtained at zero bias voltage. Additionally, this doping method is also utilized to realize a complementary inverter with a voltage gain of 24. By configuring 2D p-MoTe2 and n-MoSe2 on demand, logic functions of NAND and NOR gates are also accomplished successfully. These results present a significant potential toward future larger-scale heterogeneously integrated 2D electronics and optoelectronics.
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Affiliation(s)
- Wennan Hu
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Hu Wang
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Jianguo Dong
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Haoran Sun
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Yue Wang
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Zhe Sheng
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Zengxing Zhang
- State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
- National Integrated Circuit Innovation Center, No. 825 Zhangheng Road, Shanghai 201203, China
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72
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Li Z, Zheng Y, Li G, Wang H, Zhu W, Wang H, Chen Z, Yuan Y, Zeng XC, Wu Y. Resolving Interface Barrier Deviation from the Schottky-Mott Rule: A Mitigation Strategy via Engineering MoS 2-Metal van der Waals Contact. J Phys Chem Lett 2023; 14:2940-2949. [PMID: 36930804 DOI: 10.1021/acs.jpclett.3c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The Schottky barrier (SB) in the ultraclean van der Waals contact between two-dimensional (2D) MoS2 and three-dimensional (3D) indium (In) strikingly deviates from the Schottky-Mott limit (SML). Herein, on the basis of first-principles calculation, the origin of the SB deviation is brought to bear, as well as a strategy for mitigating the SB deviation. In light of the good agreement between the SB and the corrected SB by interface potential difference (ΔV) and Fermi -level shift (ΔEF) based on the SML, the SB deviation is attributed to the combined effects of ΔV and ΔEF. Furthermore, when a Au, Sc, or Ti thin film is coated on the back side of In, the SB deviation and the sum of ΔV and ΔEF decrease similarly. Importantly, in the Ti coating situation, the SB is reduced to 0.12 eV, notably smaller than the value of 0.30 eV in the Au coating case. This interface engineering can be generalized to regulate the SB between a 2D semiconductor and a 3D alloy.
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Affiliation(s)
- Zhongjun Li
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
- State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China
| | - Yahui Zheng
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Guojun Li
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Hanxi Wang
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Weiduo Zhu
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Haidi Wang
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Zhao Chen
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
| | - Yupeng Yuan
- School of Materials Science and Engineering, Anhui University, Hefei 2300601, Anhui, China
| | - Xiao Cheng Zeng
- Department of Materials Science & Engineering, City University of Hong Kong, Kowloon 999077, Hong Kong, China
- Department of Chemistry, University of Nebraska─Lincoln, Lincoln, Nebraska 68588, United States
| | - Yucheng Wu
- School of Physics, Hefei University of Technology, Hefei 230009, Anhui, China
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73
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Wang Z, Wei L, Wang S, Wu T, Sun L, Ma C, Tao X, Wang S. 2D SiP 2/h-BN for a Gate-Controlled Phototransistor with Ultrahigh Sensitivity. ACS APPLIED MATERIALS & INTERFACES 2023; 15:15810-15818. [PMID: 36939047 DOI: 10.1021/acsami.2c19803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Two-dimensional (2D) materials are extremely attractive for the construction of highly sensitive photodetectors due to their unique electronic and optical properties. However, developing 2D photodetectors with ultrahigh sensitivity for extremely low-light-level detection is still a challenge owing to the limitation of high dark current and low detectivity. Herein, a gate-controlled phototransistor based on 2D SiP2/hexagonal boron nitride (h-BN) was rationally designed and demonstrated ultrahigh sensitivity for the first time. With a back-gate device geometry, the SiP2/h-BN phototransistor exhibits an ultrahigh detectivity of 3.4 × 1013 Jones, which is one of the highest values among 2D material-based photodetectors. In addition, the phototransistor also shows a gate tunable responsivity of ≤43.5 A/W at a gate voltage of 30 V due to the photogating effect. The ultrahigh sensitivity of the SiP2-based phototransistor is attributed to the extremely low dark current suppressed by the phototransistor configuration and the improved photocurrent by using h-BN as a substrate to reduce charge scattering. This work provides a facile strategy for improving the detectivity of photodetectors and validates the great potential of 2D SiP2 phototransistors for ultrasensitive optoelectronic applications.
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Affiliation(s)
- Ziming Wang
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Limei Wei
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Shilei Wang
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Tiange Wu
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Lanjing Sun
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Chao Ma
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Xutang Tao
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
| | - Shanpeng Wang
- State Key Laboratory of Crystal Materials and Institute of Crystal Materials, Shandong University, Jinan 250100, P. R. China
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74
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Hu Y, Hu X, Wang Y, Lu C, Krasheninnikov AV, Chen Z, Sun L. Suppressed Fermi Level Pinning and Wide-Range Tunable Schottky Barrier in CrX 3 (X = I, Br)/2D Metal Contacts. J Phys Chem Lett 2023; 14:2807-2815. [PMID: 36912604 DOI: 10.1021/acs.jpclett.3c00354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
CrX3 (X = I, Br) monolayers exhibit outstanding performance in spintronic devices. However, the Schottky barrier at the CrX3/electrode interface severely impedes the charge injection efficiency. Herein, we propose two-dimensional (2D) metals as electrodes to form van der Waals (vdW) contact with CrX3 monolayers and systematically explore the contact properties of CrX3/metal by density functional theory (DFT) calculations. The results demonstrate that the strongly suppressed Fermi level pinning (FLP) effect and the wide-range tunable Schottky barrier can be achieved in CrX3/metal contacts. Specifically, the n-type and the p-type Schottky contacts can be realized in CrX3/metal contacts by choosing 2D metal electrodes with different work functions. Importantly, the pinning factors for CrX3/metal contacts are exceptionally larger than other commonly studied 2D semiconductors, indicating the strongly suppressed FLP in CrX3/metal contacts, which leads to the wide-range tunable Schottky barrier. Our findings provide guidance to the choice of electrodes and promote the development of CrX3-based spin devices.
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Affiliation(s)
- Yanmei Hu
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Xiaohui Hu
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China
| | - Yifeng Wang
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China
| | - Chunhua Lu
- College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, China
- Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites, Nanjing Tech University, Nanjing 211816, China
| | - Arkady V Krasheninnikov
- Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, 01314 Dresden, Germany
- Department of Applied Physics, Aalto University School of Science, P.O. Box 11100, 00076 Aalto, Finland
| | - Zhongfang Chen
- Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, Puerto Rico 00931, United States
| | - Litao Sun
- SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing 210096, China
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75
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Ali N, Lee M, Ali F, Ngo TD, Park H, Shin H, Yoo WJ. Percolation-Based Metal-Insulator Transition in Black Phosphorus Field Effect Transistors. ACS APPLIED MATERIALS & INTERFACES 2023; 15:13299-13306. [PMID: 36856371 DOI: 10.1021/acsami.2c22046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The existence of a novel phenomenon, such as the metal-insulator transition (MIT) in two-dimensional (2D) systems, affords emerging functional properties that provide new aspects for future electronics and optoelectronics. Here, we report the observation of the MIT in black phosphorus field effect transistors by tuning the carrier density (n) controlled by back-gate bias. We find that the conductivity follows an n dependence as σ(n) ∝ nα with α ∼ 1, which indicates the presence of screened Coulomb impurity scattering at high carrier densities in the temperature range of 10-300 K. As n decreases, the screened Coulomb impurity scattering breaks down, developing strong charge density inhomogeneity leading to a percolation-based transition at the critical carrier density (nC). At low carrier densities (n < nC), the system is in the insulating regime, which is expressed by Mott variable range hopping that demonstrates the role of disorder in the system. In addition, the extracted average values of critical exponent δ are ∼1.29 ± 0.01 and ∼1.14 ± 0.01 for devices A and B, respectively, consistent with the 2D percolation exponent of 4/3, confirming the 2D percolation-based MIT in BP devices. Our findings strongly suggest that the 2D MIT observed in BP is a classical percolation-based transition caused by charge inhomogeneity induced by screened Coulomb charge impurity scattering around a transition point controlled by n through back-gate bias.
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Affiliation(s)
- Nasir Ali
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Myeongjin Lee
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Fida Ali
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Tien Dat Ngo
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Hyokwang Park
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Hoseong Shin
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
| | - Won Jong Yoo
- SKKU Advanced Institute of Nano-Technology (SAINT), Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Korea
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76
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Zhang G, Lu G, Li X, Mei Z, Liang L, Fan S, Li Q, Wei Y. Reconfigurable Two-Dimensional Air-Gap Barristors. ACS NANO 2023; 17:4564-4573. [PMID: 36847653 DOI: 10.1021/acsnano.2c10593] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Reconfigurable logic circuits implemented by two-dimensional (2D) ambipolar semiconductors provide a prospective solution for the post-Moore era. It is still a challenge for ambipolar nanomaterials to realize reconfigurable polarity control and rectification with a simplified device structure. Here, an air-gap barristor based on an asymmetric stacking sequence of the electrode contacts was developed to resolve these issues. For the 2D ambipolar channel of WSe2, the barristor can not only be reconfigured as an n- or p-type unipolar transistor but also work as a switchable diode. The air gap around the bottom electrode dominates the reconfigurable behaviors by widening the Schottky barrier here, thus blocking the injection of both electrons and holes. The electrical performances can be improved by optimizing the electrode materials, which achieve an on/off ratio of 104 for the transistor and a rectifying ratio of 105 for the diode. A complementary inverter and a switchable AND/OR logic gate were constructed by using the air-gap barristors as building blocks. This work provides an efficient approach with great potential for low-dimensional reconfigurable electronics.
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Affiliation(s)
- Guangqi Zhang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Gaotian Lu
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Xuanzhang Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Zhen Mei
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Liang Liang
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Shoushan Fan
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Qunqing Li
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
| | - Yang Wei
- State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China
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77
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Schock RTK, Neuwald J, Möckel W, Kronseder M, Pirker L, Remškar M, Hüttel AK. Non-Destructive Low-Temperature Contacts to MoS 2 Nanoribbon and Nanotube Quantum Dots. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2209333. [PMID: 36624967 DOI: 10.1002/adma.202209333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Molybdenum disulfide nanoribbons and nanotubes are quasi-1D semiconductors with strong spin-orbit interaction, a nanomaterial highly promising for quantum electronic applications. Here, it is demonstrated that a bismuth semimetal layer between the contact metal and this nanomaterial strongly improves the properties of the contacts. Two-point resistances on the order of 100 kΩ are observed at room temperature. At cryogenic temperature, Coulomb blockade is visible. The resulting stability diagrams indicate a marked absence of trap states at the contacts and the corresponding disorder, compared to previous devices that use low-work-function metals as contacts. Single-level quantum transport is observed at temperatures below 100 mK.
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Affiliation(s)
- Robin T K Schock
- Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
| | - Jonathan Neuwald
- Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
| | - Wolfgang Möckel
- Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
| | - Matthias Kronseder
- Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
| | - Luka Pirker
- Solid State Physics Department, Jožef Stefan Institute, 1000, Ljubljana, Slovenia
- J. Heyrovský Institute of Physical Chemistry, v.v.i., Czech Academy of Sciences, 182 23, Prague, Czech Republic
| | - Maja Remškar
- Solid State Physics Department, Jožef Stefan Institute, 1000, Ljubljana, Slovenia
| | - Andreas K Hüttel
- Institute for Experimental and Applied Physics, University of Regensburg, 93040, Regensburg, Germany
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78
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Improvements in 2D p-type WSe 2 transistors towards ultimate CMOS scaling. Sci Rep 2023; 13:3304. [PMID: 36849724 PMCID: PMC9971212 DOI: 10.1038/s41598-023-30317-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/21/2023] [Indexed: 03/01/2023] Open
Abstract
This paper provides comprehensive experimental analysis relating to improvements in the two-dimensional (2D) p-type metal-oxide-semiconductor (PMOS) field effect transistors (FETs) by pure van der Waals (vdW) contacts on few-layer tungsten diselenide (WSe2) with high-k metal gate (HKMG) stacks. Our analysis shows that standard metallization techniques (e.g., e-beam evaporation at moderate pressure ~ 10-5 torr) results in significant Fermi-level pinning, but Schottky barrier heights (SBH) remain small (< 100 meV) when using high work function metals (e.g., Pt or Pd). Temperature-dependent analysis uncovers a more dominant contribution to contact resistance from the channel access region and confirms significant improvement through less damaging metallization techniques (i.e., reduced scattering) combined with strongly scaled HKMG stacks (enhanced carrier density). A clean contact/channel interface is achieved through high-vacuum evaporation and temperature-controlled stepped deposition providing large improvements in contact resistance. Our study reports low contact resistance of 5.7 kΩ-µm, with on-state currents of ~ 97 µA/µm and subthreshold swing of ~ 140 mV/dec in FETs with channel lengths of 400 nm. Furthermore, theoretical analysis using a Landauer transport ballistic model for WSe2 SB-FETs elucidates the prospects of nanoscale 2D PMOS FETs indicating high-performance (excellent on-state current vs subthreshold swing benchmarks) towards the ultimate CMOS scaling limit.
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79
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Wafer-scale and universal van der Waals metal semiconductor contact. Nat Commun 2023; 14:1014. [PMID: 36823424 PMCID: PMC9950472 DOI: 10.1038/s41467-023-36715-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 02/13/2023] [Indexed: 02/25/2023] Open
Abstract
Van der Waals (vdW) metallic contacts have been demonstrated as a promising approach to reduce the contact resistance and minimize the Fermi level pinning at the interface of two-dimensional (2D) semiconductors. However, only a limited number of metals can be mechanically peeled and laminated to fabricate vdW contacts, and the required manual transfer process is not scalable. Here, we report a wafer-scale and universal vdW metal integration strategy readily applicable to a wide range of metals and semiconductors. By utilizing a thermally decomposable polymer as the buffer layer, different metals were directly deposited without damaging the underlying 2D semiconductor channels. The polymer buffer could be dry-removed through thermal annealing. With this technique, various metals could be vdW integrated as the contact of 2D transistors, including Ag, Al, Ti, Cr, Ni, Cu, Co, Au, Pd. Finally, we demonstrate that this vdW integration strategy can be extended to bulk semiconductors with reduced Fermi level pinning effect.
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80
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Ho PH, Chang JR, Chen CH, Hou CH, Chiang CH, Shih MC, Hsu HC, Chang WH, Shyue JJ, Chiu YP, Chen CW. Hysteresis-Free Contact Doping for High-Performance Two-Dimensional Electronics. ACS NANO 2023; 17:2653-2660. [PMID: 36716244 DOI: 10.1021/acsnano.2c10631] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Contact doping is considered crucial for reducing the contact resistance of two-dimensional (2D) transistors. However, a process for achieving robust contact doping for 2D electronics is lacking. Here, we developed a two-step doping method for effectively doping 2D materials through a defect-repairing process. The method achieves strong and hysteresis-free doping and is suitable for use with the most widely used transition-metal dichalcogenides. Through our method, we achieved a record-high sheet conductance (0.16 mS·sq-1 without gating) of monolayer MoS2 and a high mobility and carrier concentration (4.1 × 1013 cm-2). We employed our robust method for the successful contact doping of a monolayer MoS2 Au-contact device, obtaining a contact resistance as low as 1.2 kΩ·μm. Our method represents an effective means of fabricating high-performance 2D transistors.
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Affiliation(s)
- Po-Hsun Ho
- Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 106, Taiwan
| | - Jun-Ru Chang
- Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Chun-Hsiang Chen
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Cheng-Hung Hou
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Chun-Hao Chiang
- Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
| | - Min-Chuan Shih
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Hung-Chang Hsu
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Wen-Hao Chang
- Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu 300, Taiwan
| | - Jing-Jong Shyue
- Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan
| | - Ya-Ping Chiu
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 106, Taiwan
- Department of Physics, National Taiwan University, Taipei 106, Taiwan
| | - Chun-Wei Chen
- Department of Materials Science and Engineering, National Taiwan University, Taipei 106, Taiwan
- Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 106, Taiwan
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81
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Pradhan NR, Garcia C, Chakrabarti B, Rosenmann D, Divan R, Sumant AV, Miller S, Hilton D, Karaiskaj D, McGill SA. Insulator-to-metal phase transition in a few-layered MoSe 2 field effect transistor. NANOSCALE 2023; 15:2667-2673. [PMID: 36652441 DOI: 10.1039/d2nr05019f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The metal-to-insulator phase transition (MIT) in low-dimensional materials and particularly two-dimensional layered semiconductors is exciting to explore due to the fact that it challenges the prediction that a two-dimensional system must be insulating at low temperatures. Thus, the exploration of MITs in 2D layered semiconductors expands the understanding of the underlying physics. Here we report the MIT of a few-layered MoSe2 field effect transistor under a gate bias (electric field) applied perpendicular to the MoSe2 layers. With low applied gate voltage, the conductivity as a function of temperature from 150 K to 4 K shows typical semiconducting to insulating character. Above a critical applied gate voltage, Vc, the conductivity becomes metallic (i.e., the conductivity increases continuously as a function of decreasing temperature). Evidence of a metallic state was observed using an applied gate voltage or, equivalently, increasing the density of charge carriers within the 2D channel. We analyzed the nature of the phase transition using percolation theory, where conductivity scales with the density of charge carriers as σ ∝ (n - nc)δ. The critical exponent for a percolative phase transition, δ(T), has values ranging from 1.34 (at T = 150 K) to 2 (T = 20 K), which is close to the theoretical value of 1.33 for percolation to occur. Thus we conclude that the MIT in few-layered MoSe2 is driven by charge carrier percolation. Furthermore, the conductivity does not scale with temperature, which is a hallmark of a quantum critical phase transition.
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Affiliation(s)
- Nihar R Pradhan
- Layered Materials and Device Physics Laboratory, Department of Chemistry, Physics and Atmospheric Science, Jackson State University, Jackson, MS 39217, USA.
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA.
| | - Carlos Garcia
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA.
- Department of Physics, Florida State University, 77 Chieftan Way, Tallahassee, FL 32306, USA
| | - Bhaswar Chakrabarti
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
- Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, Tamil Nadu-600036, India
| | - Daniel Rosenmann
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
| | - Ralu Divan
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
| | - Anirudha V Sumant
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
| | - Suzanne Miller
- Center for Nanoscale Materials, Argonne National Laboratory, 9700 S-Cass Avenue, Lemont, IL-60439, USA
| | - David Hilton
- Department of Physics, Baylor University, One Bear Place 97316, Waco, TX 76798-7316, USA
| | - Denis Karaiskaj
- Department of Physics, University of South Florida, Tampa, FL 33620, USA
| | - Stephen A McGill
- National High Magnetic Field Laboratory, 1800 E. Paul Dirac Dr., Tallahassee, FL 32310, USA.
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82
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Lee Y, Chang Y, Ryu H, Kim JH, Watanabe K, Taniguchi T, Kim M, Lee GH. Quasi-van der Waals Epitaxial Recrystallization of a Gold Thin Film into Crystallographically Aligned Single Crystals. ACS APPLIED MATERIALS & INTERFACES 2023; 15:6092-6097. [PMID: 36577086 DOI: 10.1021/acsami.2c18514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Heterointerfaces between two-dimensional (2D) materials and bulk metals determine the electrical and optical properties of their heterostructures. Although deposition of various metals on 2D materials has been studied, there is still a lack of studies on the interaction at the van der Waals (vdW) heterointerface between 2D materials and metals. Here, we report quasi-van der Waals (qvdW) epitaxial recrystallization of a gold thin film into crystallographically aligned single crystals by encapsulation annealing of a gold thin film with hexagonal boron nitride (hBN). When a polycrystalline gold thin film passivated with hBN was annealed, it was recrystallized into single gold crystals with a planar shape and crystallographic alignment with hBN due to a strong interaction between the gold film and hBN at the heterointerface. This reflects that a weak vdW force at the heterointerface is sufficiently strong to induce epitaxial recrystallization. Using this method, we fabricated a gold nanocrystal array with the same crystalline orientation and smooth top surface. Our work demonstrates a new method for epitaxial recrystallization of bulk crystals and provides a deep understanding of the interaction at the vdW heterointerface of 2D materials and metals.
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Affiliation(s)
- Yuna Lee
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Yunyeong Chang
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Huije Ryu
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Jong Hun Kim
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute of Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Miyoung Kim
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Gwan-Hyoung Lee
- Materials Science and Engineering, Seoul National University, Seoul 08826, Korea
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83
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Aftab S, Iqbal MZ, Rim YS. Recent Advances in Rolling 2D TMDs Nanosheets into 1D TMDs Nanotubes/Nanoscrolls. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2205418. [PMID: 36373722 DOI: 10.1002/smll.202205418] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/25/2022] [Indexed: 06/16/2023]
Abstract
Transition metal dichalcogenides (TMDs) van der Waals (vdW) 1D heterostructures are recently synthesized from 2D nanosheets, which open up new opportunities for potential applications in electronic and optoelectronic devices. The most recent and promising strategies in regards to forming 1D TMDs nanotubes (NTs) or nanoscrolls (NSs) in this review article as well as their heterostructures that are produced from 2D TMDs are summarized. In order to improve the functionality of ultrathin 1D TMDs that are coaxially combined with boron nitride nanotubes and single-walled carbon nanotubes. 1D heterostructured devices perform better than 2D TMD nanosheets when the two devices are compared. The photovoltaic effect in WS2 or MoS2 NTs without a junction may exceed the Shockley-Queisser limit for the above-band-gap photovoltage generation. Photoelectrochemical hydrogen evolution is accelerated when monolayer WS2 or MoS2 NSs are incorporated into a heterojunction. In addition, the photovoltaic performance of the WSe2 /MoS2 NSs junction is superior to that of the performance of MoS2 NSs. The summary of the current research about 1D TMDs can be used in a variety of ways, which assists in the development of new types of nanoscale optoelectronic devices. Finally, it also summarizes the current challenges and prospects.
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Affiliation(s)
- Sikandar Aftab
- Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, 05006, South Korea
| | - Muhammad Zahir Iqbal
- Faculty of Engineering Sciences, Ghulam Ishaq Khan Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640, Pakistan
| | - You Seung Rim
- Department of Intelligent Mechatronics Engineering, Sejong University, Seoul, 05006, South Korea
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84
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Zhuo F, Wu J, Li B, Li M, Tan CL, Luo Z, Sun H, Xu Y, Yu Z. Modifying the Power and Performance of 2-Dimensional MoS 2 Field Effect Transistors. RESEARCH (WASHINGTON, D.C.) 2023; 6:0057. [PMID: 36939429 PMCID: PMC10016345 DOI: 10.34133/research.0057] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/02/2023] [Indexed: 01/13/2023]
Abstract
Over the past 60 years, the semiconductor industry has been the core driver for the development of information technology, contributing to the birth of integrated circuits, Internet, artificial intelligence, and Internet of Things. Semiconductor technology has been evolving in structure and material with co-optimization of performance-power-area-cost until the state-of-the-art sub-5-nm node. Two-dimensional (2D) semiconductors are recognized by the industry and academia as a hopeful solution to break through the quantum confinement for the future technology nodes. In the recent 10 years, the key issues on 2D semiconductors regarding material, processing, and integration have been overcome in sequence, making 2D semiconductors already on the verge of application. In this paper, the evolution of transistors is reviewed by outlining the potential of 2D semiconductors as a technological option beyond the scaled metal oxide semiconductor field-effect transistors. We mainly focus on the optimization strategies of mobility (μ), equivalent oxide thickness (EOT), and contact resistance (RC ), which enables high ON current (Ion ) with reduced driving voltage (Vdd ). Finally, we prospect the semiconductor technology roadmap by summarizing the technological development of 2D semiconductors over the past decade.
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Affiliation(s)
- Fulin Zhuo
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Jie Wu
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Binhong Li
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- Institute of Microelectronics,
Chinese Academy of Sciences, Beijing 100029, China
- Address correspondence to: (B.L.); (Z.L.); (H.S.); (Y.X.); (Z.Y.)
| | - Moyang Li
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Chee Leong Tan
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
| | - Zhongzhong Luo
- College of Electronic and Optical Engineering and College of Flexible Electronics (Future Technology),
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Address correspondence to: (B.L.); (Z.L.); (H.S.); (Y.X.); (Z.Y.)
| | - Huabin Sun
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- Address correspondence to: (B.L.); (Z.L.); (H.S.); (Y.X.); (Z.Y.)
| | - Yong Xu
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- Address correspondence to: (B.L.); (Z.L.); (H.S.); (Y.X.); (Z.Y.)
| | - Zhihao Yu
- College of Integrated Circuit Science and Engineering,
Nanjing University of Posts and Telecommunications, Nanjing 210023, China
- Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangzhou 510535, China
- Address correspondence to: (B.L.); (Z.L.); (H.S.); (Y.X.); (Z.Y.)
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85
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Sun Y, Jiang L, Wang Z, Hou Z, Dai L, Wang Y, Zhao J, Xie YH, Zhao L, Jiang Z, Ren W, Niu G. Multiwavelength High-Detectivity MoS 2 Photodetectors with Schottky Contacts. ACS NANO 2022; 16:20272-20280. [PMID: 36508482 DOI: 10.1021/acsnano.2c06062] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Photodetection is one of the vital functions for the multifunctional "More than Moore" (MtM) microchips urgently required by Internet of Things (IoT) and artificial intelligence (AI) applications. The further improvement of the performance of photodetectors faces various challenges, including materials, fabrication processes, and device structures. We demonstrate in this work MoS2 photodetectors with a nanoscale channel length and a back-gate device structure. With the mechanically exfoliated six-monolayer-thick MoS2, a Schottky contact between source/drain electrodes and MoS2, a high responsivity of 4.1 × 103 A W-1, and a detectivity of 1.34 × 1013 cm Hz1/2 W-1 at 650 nm were achieved. The devices are also sensitive to multiwavelength lights, including 520 and 405 nm. The electrical and optoelectronic properties of the MoS2 photodetectors were studied in depth, and the working mechanism of the devices was analyzed. The photoinduced Schottky barrier lowering (PIBL) was found to be important for the high performance of the phototransistor.
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Affiliation(s)
- Yanxiao Sun
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Luyue Jiang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Zhe Wang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Zhenfei Hou
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Liyan Dai
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Yankun Wang
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Jinyan Zhao
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Ya-Hong Xie
- Department of Materials Science and Engineering, University of California, Los Angeles, Los AngelesCalifornia90024, United States
| | - Libo Zhao
- The State Key Laboratory for Manufacturing Systems Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Zhuangde Jiang
- The State Key Laboratory for Manufacturing Systems Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Wei Ren
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
| | - Gang Niu
- Electronic Materials Research Laboratory, Key Laboratory of the Ministry of Education & International Center for Dielectric Research, School of Electronic Science and Engineering & The International Joint Laboratory for Micro/Nano Manufacturing and Measurement Technology, Xi'an Jiaotong University, Xi'an710049, People's Republic of China
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86
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Miao J, Wu L, Bian Z, Zhu Q, Zhang T, Pan X, Hu J, Xu W, Wang Y, Xu Y, Yu B, Ji W, Zhang X, Qiao J, Samorì P, Zhao Y. A "Click" Reaction to Engineer MoS 2 Field-Effect Transistors with Low Contact Resistance. ACS NANO 2022; 16:20647-20655. [PMID: 36455073 DOI: 10.1021/acsnano.2c07670] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) materials with the atomically thin thickness have attracted great interest in the post-Moore's Law era because of their tremendous potential to continue transistor downscaling and offered advances in device performance at the atomic limit. However, the metal-semiconductor contact is the bottleneck in field-effect transistors (FETs) integrating 2D semiconductors as channel materials. A robust and tunable doping method at the source and drain region of 2D transistors to minimize the contact resistance is highly sought after. Here we report a stable carrier doping method via the mild covalent grafting of maleimides on the surface of 2D transition metal dichalcogenides. The chemisorbed interaction contributes to the efficient carrier doping without degrading the high-performance carrier transport. Density functional theory results further illustrate that the molecular functionalization leads to the mild hybridization and the negligible impact on the conduction bands of monolayer MoS2, avoiding the random scattering from the dopants. Differently from reported molecular treatments, our strategy displays high thermal stability (above 300 °C) and it is compatible with micro/nano processing technology. The contact resistance of MoS2 FETs can be greatly reduced by ∼12 times after molecular functionalization. The Schottky barrier of 44 meV is achieved on monolayer MoS2 FETs, demonstrating efficient charge injection between metal and 2D semiconductor. The mild covalent functionalization of molecules on 2D semiconductors represents a powerful strategy to perform the carrier doping and the device optimization.
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Affiliation(s)
- Jialei Miao
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
- Department of Electrical Engineering and Computer Science, Ningbo University, Ningbo315211, China
| | - Linlu Wu
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing100872, China
| | - Zheng Bian
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Qinghai Zhu
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Tianjiao Zhang
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Xin Pan
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Jiayang Hu
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Wei Xu
- Research Centre for Humanoid Sensing, Zhejiang Lab, Hangzhou311121, China
| | - Yeliang Wang
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing100081, China
| | - Yang Xu
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Bin Yu
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing100872, China
| | - Xiaowei Zhang
- Department of Electrical Engineering and Computer Science, Ningbo University, Ningbo315211, China
| | - Jingsi Qiao
- MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices, School of Integrated Circuits and Electronics, Beijing Institute of Technology, Beijing100081, China
| | - Paolo Samorì
- University of Strasbourg, CNRS, ISIS UMR 7006, 8 allée Gaspard Monge, F-67000Strasbourg, France
| | - Yuda Zhao
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou310027, China
- Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, Jianghan University, Wuhan430056, China
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87
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Hwa Y, Chee SS. Improvement of Visible Photodetection of Chemical Vapor Deposition-Grown MoS 2 Devices via Graphene/Au Contacts. SENSORS (BASEL, SWITZERLAND) 2022; 22:9687. [PMID: 36560055 PMCID: PMC9783588 DOI: 10.3390/s22249687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 06/17/2023]
Abstract
Two-dimensional (2D) molybdenum disulfide (MoS2) is a promising material for constructing high-performance visible photosensor arrays because of its high mobility and scale-up process. These distinct properties enable the construction of practical optoelectrical sensor arrays. However, contact engineering for MoS2 films is not still optimized. In this work, we inserted a graphene interlayer between the MoS2 films and Au contacts (graphene/Au) via the wet-transfer method to boost the device performance. Using graphene/Au contacts, outstanding electrical properties, namely field-effect mobility of 12.06 cm2/V∙s, on/off current ratio of 1.0 × 107, and responsivity of 610 A/W under illumination at 640 nm, were achieved. These favorable results were from the Fermi-level depinning effect induced by the graphene interlayer. Our results may help to construct large-area photonic sensor arrays based on 2D materials.
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Affiliation(s)
- Yeongsik Hwa
- Nano Convergence Materials Center, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851, Republic of Korea
- School of Materials Science and Engineering, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Sang-Soo Chee
- Nano Convergence Materials Center, Korea Institute of Ceramic Engineering and Technology (KICET), Jinju 52851, Republic of Korea
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88
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Yan Y, Li J, Li S, Wang M, Luo G, Song X, Zhang S, Jiang Y, Qin R, Xia C. Two-dimensional wide-bandgap GeSe 2 vertical ultraviolet photodetectors with high responsivity and ultrafast response speed. NANOSCALE ADVANCES 2022; 4:5297-5303. [PMID: 36540128 PMCID: PMC9724610 DOI: 10.1039/d2na00565d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 06/17/2023]
Abstract
Germanium selenide (GeSe2), as a typical member of 2D wide bandgap semiconductors (WBSs), shows great potential in ultraviolet (UV) optoelectronics due to its excellent flexibility, superior environmental stability, competitive UV absorption coefficient, and significant spectral selectivity. However, the GeSe2-based UV photodetector suffers from high operation voltages and low photocurrent, which prevents its practical imaging applications. In this work, we report an elevated photocurrent generation in a vertical stacking graphene/GeSe2/graphene heterostructure with low operation voltage and low power consumption. Efficient collection of photoexcited carriers in GeSe2 through graphene electrodes results in outstanding UV detection properties, including a pronounced responsivity of 37.1 A W-1, a specific detectivity of 8.83 × 1011 Jones, and an ultrahigh on/off ratio (∼105) at 355 nm. In addition, building a Schottky barrier between GeSe2 and graphene and reducing the channel length can increase the photoresponse speed to ∼300 μs. These accomplishments set the stage for future optoelectronic applications of vertical 2D WBS heterostructure UV photodetectors.
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Affiliation(s)
- Yong Yan
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Jie Li
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Shasha Li
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Mengna Wang
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Gaoli Luo
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Xiaohui Song
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Suicai Zhang
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Yurong Jiang
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Ruiping Qin
- School of Physics, Henan Normal University Xinxiang Henan province China
| | - Congxin Xia
- School of Physics, Henan Normal University Xinxiang Henan province China
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89
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Shen Y, Dong Z, Sun Y, Guo H, Wu F, Li X, Tang J, Liu J, Wu X, Tian H, Ren TL. The Trend of 2D Transistors toward Integrated Circuits: Scaling Down and New Mechanisms. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2201916. [PMID: 35535757 DOI: 10.1002/adma.202201916] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/12/2022] [Indexed: 06/14/2023]
Abstract
2D transition metal chalcogenide (TMDC) materials, such as MoS2 , have recently attracted considerable research interest in the context of their use in ultrascaled devices owing to their excellent electronic properties. Microprocessors and neural network circuits based on MoS2 have been developed at a large scale but still do not have an advantage over silicon in terms of their integrated density. In this study, the current structures, contact engineering, and doping methods for 2D TMDC materials for the scaling-down process and performance optimization are reviewed. Devices are introduced according to a new mechanism to provide the comprehensive prospects for the use of MoS2 beyond the traditional complementary-metal-oxide semiconductor in order to summarize obstacles to the goal of developing high-density and low-power integrated circuits (ICs). Finally, prospects for the use of MoS2 in large-scale ICs from the perspectives of the material, system performance, and application to nonlogic functionalities such as sensor circuits and analogous circuits, are briefly analyzed. The latter issue is along the direction of "more than Moore" research.
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Affiliation(s)
- Yang Shen
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist) School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China
| | - Zuoyuan Dong
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - Yabin Sun
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - Hao Guo
- Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, School of Instrument and Electronics, North University of China, Taiyuan, Shanxi, 030051, China
| | - Fan Wu
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist) School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China
| | - Xianglong Li
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - Jun Tang
- Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, School of Instrument and Electronics, North University of China, Taiyuan, Shanxi, 030051, China
| | - Jun Liu
- Shanxi Province Key Laboratory of Quantum Sensing and Precision Measurement, School of Instrument and Electronics, North University of China, Taiyuan, Shanxi, 030051, China
| | - Xing Wu
- Shanghai Key Laboratory of Multidimensional Information Processing, School of Communication and Electronic Engineering, East China Normal University, Shanghai, 200241, China
| | - He Tian
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist) School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China
| | - Tian-Ling Ren
- Institute of Microelectronics and Beijing National Research Center for Information Science and Technology (BNRist) School of Integrated Circuits and Beijing National Research Center for Information Science and Technology (BNRist), Tsinghua University, Beijing, 100084, China
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90
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Cao Q, Telford EJ, Benyamini A, Kennedy I, Zangiabadi A, Watanabe K, Taniguchi T, Dean CR, Hunt BM. Tunneling Spectroscopy of Two-Dimensional Materials Based on Via Contacts. NANO LETTERS 2022; 22:8941-8948. [PMID: 36356229 DOI: 10.1021/acs.nanolett.2c03081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
We introduce a novel planar tunneling architecture for van der Waals heterostructures based on via contacts, namely, metallic contacts embedded into through-holes in hexagonal boron nitride (hBN). We use the via-based tunneling method to study the single-particle density of states of two different two-dimensional (2D) materials, NbSe2 and graphene. In NbSe2 devices, we characterize the barrier strength and interface disorder for barrier thicknesses of 0, 1, and 2 layers of hBN and study the dependence on the tunnel-contact area down to (44 ± 14)2 nm2. For 0-layer hBN devices, we demonstrate a crossover from diffusive to point contacts in the small-contact-area limit. In graphene, we show that reducing the tunnel barrier thickness and area can suppress effects due to phonon-assisted tunneling and defects in the hBN barrier. This via-based architecture overcomes limitations of other planar tunneling designs and produces high-quality, ultraclean tunneling structures from a variety of 2D materials.
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Affiliation(s)
- Qingrui Cao
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States
| | - Evan J Telford
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Avishai Benyamini
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Ian Kennedy
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Amirali Zangiabadi
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York10027, United States
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba305-0044, Japan
| | - Cory R Dean
- Department of Physics, Columbia University, New York, New York10027, United States
| | - Benjamin M Hunt
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania15213, United States
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91
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Adam T, Dhahi TS, Gopinath SCB, Hashim U. Novel Approaches in Fabrication and Integration of Nanowire for Micro/Nano Systems. Crit Rev Anal Chem 2022; 52:1913-1929. [DOI: 10.1080/10408347.2021.1925523] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Tijjani Adam
- Faculty of Electronic Engineering Technology, Universiti Malaysia Perlis, Perlis, Malaysia
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, Perlis, Malaysia
| | | | - Subash C. B. Gopinath
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, Perlis, Malaysia
- Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis, Perlis, Malaysia
| | - Uda Hashim
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis, Perlis, Malaysia
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92
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Zhang X, Zhang Y, Yu H, Zhao H, Cao Z, Zhang Z, Zhang Y. Van der Waals-Interface-Dominated All-2D Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2207966. [PMID: 36353883 DOI: 10.1002/adma.202207966] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/06/2022] [Indexed: 06/16/2023]
Abstract
The interface is the device. As the feature size rapidly shrinks, silicon-based electronic devices are facing multiple challenges of material performance decrease and interface quality degradation. Ultrathin 2D materials are considered as potential candidates in future electronics by their atomically flat surfaces and excellent immunity to short-channel effects. Moreover, due to naturally terminated surfaces and weak van der Waals (vdW) interactions between layers, 2D materials can be freely stacked without the lattice matching limit to form high-quality heterostructure interfaces with arbitrary components and twist angles. Controlled interlayer band alignment and optimized interfacial carrier behavior allow all-2D electronics based on 2D vdW interfaces to exhibit more comprehensive functionality and better performance. Especially, achieving the same computing capacity of multiple conventional devices with small footprint all-2D devices is considered to be the key development direction of future electronics. Herein, the unique properties of all-2D vdW interfaces and their construction methods are systematically reviewed and the main performance contributions of different vdW interfaces in 2D electronics are summarized, respectively. Finally, the recent progress and challenges for all-2D vdW electronics are discussed, and how to improve the compatibility of 2D material devices with silicon-based industrial technology is pointed out as a critical challenge.
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Affiliation(s)
- Xiankun Zhang
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Yanzhe Zhang
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Huihui Yu
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Hang Zhao
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Zhihong Cao
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Zheng Zhang
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
| | - Yue Zhang
- Academy for Advanced Interdisciplinary Science and Technology, Beijing Advanced Innovation Center for Materials Genome Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
- Beijing Key Laboratory for Advanced Energy Materials and Technologies, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing, 100083, P. R. China
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93
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Miao J, Zhang X, Tian Y, Zhao Y. Recent Progress in Contact Engineering of Field-Effect Transistor Based on Two-Dimensional Materials. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:3845. [PMID: 36364620 PMCID: PMC9658022 DOI: 10.3390/nano12213845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/23/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Two-dimensional (2D) semiconductors have been considered as promising candidates to fabricate ultimately scaled field-effect transistors (FETs), due to the atomically thin thickness and high carrier mobility. However, the performance of FETs based on 2D semiconductors has been limited by extrinsic factors, including high contact resistance, strong interfacial scattering, and unintentional doping. Among these challenges, contact resistance is a dominant issue, and important progress has been made in recent years. In this review, the Schottky-Mott model is introduced to show the ideal Schottky barrier, and we further discuss the contribution of the Fermi-level pinning effect to the high contact resistance in 2D semiconductor devices. In 2D FETs, Fermi-level pinning is attributed to the high-energy metal deposition process, which would damage the lattice of atomically thin 2D semiconductors and induce the pinning of the metal Fermi level. Then, two contact structures and the strategies to fabricate low-contact-resistance short-channel 2D FETs are introduced. Finally, our review provides practical guidelines for the realization of high-performance 2D-semiconductors-based FETs with low contact resistance and discusses the outlook of this field.
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Affiliation(s)
- Jialei Miao
- Department of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, China
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
| | - Xiaowei Zhang
- Department of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, China
| | - Ye Tian
- Department of Electrical Engineering and Computer Science, Ningbo University, Ningbo 315211, China
| | - Yuda Zhao
- School of Micro-Nano Electronics, Hangzhou Global Scientific and Technological Innovation Centre, Zhejiang University, 38 Zheda Road, Hangzhou 310027, China
- Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education, Jianghan University, Wuhan 430056, China
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94
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The effects of point defect type, location, and density on the Schottky barrier height of Au/MoS 2 heterojunction: a first-principles study. Sci Rep 2022; 12:18001. [PMID: 36289283 PMCID: PMC9606307 DOI: 10.1038/s41598-022-22913-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/20/2022] [Indexed: 12/02/2022] Open
Abstract
Using DFT calculations, we investigate the effects of the type, location, and density of point defects in monolayer MoS2 on electronic structures and Schottky barrier heights (SBH) of Au/MoS2 heterojunction. Three types of point defects in monolayer MoS2, that is, S monovacancy, S divacancy and MoS (Mo substitution at S site) antisite defects, are considered. The following findings are revealed: (1) The SBH for the monolayer MoS2 with these defects is universally higher than that for its defect-free counterpart. (2) S divacancy and MoS antisite defects increase the SBH to a larger extent than S monovacancy. (3) A defect located in the inner sublayer of MoS2, which is adjacent to Au substrate, increases the SBH to a larger extent than that in the outer sublayer of MoS2. (4) An increase in defect density increases the SBH. These findings indicate a large variation of SBH with the defect type, location, and concentration. We also compare our results with previously experimentally measured SBH for Au/MoS2 contact and postulate possible reasons for the large differences among existing experimental measurements and between experimental measurements and theoretical predictions. The findings and insights revealed here may provide practical guidelines for modulation and optimization of SBH in Au/MoS2 and similar heterojunctions via defect engineering.
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95
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Ding D, Wang S, Xia Y, Li P, He D, Zhang J, Zhao S, Yu G, Zheng Y, Cheng Y, Xie M, Ding F, Jin C. Atomistic Insight into the Epitaxial Growth Mechanism of Single-Crystal Two-Dimensional Transition-Metal Dichalcogenides on Au(111) Substrate. ACS NANO 2022; 16:17356-17364. [PMID: 36200750 DOI: 10.1021/acsnano.2c08188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
A mechanistic understanding of interactions between atomically thin two-dimensional (2D) transition-metal dichalcogenides (TMDs) and their growth substrates is important for achieving the unidirectional alignment of nuclei and seamless stitching of 2D TMD domains and thus 2D wafers. In this work, we conduct a cross-sectional scanning transmission electron microscopy (STEM) study to investigate the atomic-scale nucleation and early stage growth behaviors of chemical vapor deposited monolayer (ML-) MoS2 and molecular beam epitaxy ML-MoSe2 on a Au(111) substrate. Statistical analysis reveals the majority of as-grown domains, i.e., ∼88% for MoS2 and 90% for MoSe2, nucleate on surface terraces, with the rest (i.e., ∼12% for MoS2 and 10% for MoSe2) on surface steps. Moreover, within the latter case, step-associated nucleation, ∼64% of them are terminated with a Mo-zigzag edge in connection with the Au surface steps, with the rest (∼36%) being S-zigzag edges. In conjunction with ab initio density functional theory calculations, the results confirm that van der Waals epitaxy, rather than the surface step guided epitaxy, plays deterministic roles for the realization of unidirectional ML-MoS2 (MoSe2) domains on a Au(111) substrate. In contrast, surface steps, particularly their step height, are mainly responsible for the integrity and thickness of MoS2/MoSe2 films. In detail, it is found that the lateral growth of monolayer thick MoS2/MoSe2 domains only proceeds across mono-Au-atom high surface steps (∼2.4 Å), but fail for higher ones (bi-Au atom step and higher) during the growth. Our cross-sectional STEM study also confirms the existence of considerable compressive residual strain that reaches ∼3.0% for ML-MoS2/MoSe2 domains on Au(111). The present study aims to understand the growth mechanism of 2D TMD wafers.
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Affiliation(s)
- Degong Ding
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Shuang Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Yipu Xia
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Pai Li
- Center for Multidimensional Carbon Materials, Institute for Basic Science, School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Daliang He
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Junqiu Zhang
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Sunwen Zhao
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Guanghui Yu
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Yonghui Zheng
- Key Laboratory of Polar Materials and Devices and Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Yan Cheng
- Key Laboratory of Polar Materials and Devices and Department of Electronics, East China Normal University, Shanghai 200241, China
| | - Maohai Xie
- Physics Department, The University of Hong Kong, Pokfulam Road, Hong Kong
| | - Feng Ding
- Center for Multidimensional Carbon Materials, Institute for Basic Science, School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 44919, Korea
| | - Chuanhong Jin
- State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
- Jihua Laboratory, Foshan, Guangdong 528200, China
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96
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Yoon HH, Fernandez HA, Nigmatulin F, Cai W, Yang Z, Cui H, Ahmed F, Cui X, Uddin MG, Minot ED, Lipsanen H, Kim K, Hakonen P, Hasan T, Sun Z. Miniaturized spectrometers with a tunable van der Waals junction. Science 2022; 378:296-299. [PMID: 36264793 DOI: 10.1126/science.add8544] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Miniaturized computational spectrometers, which can obtain incident spectra using a combination of device spectral responses and reconstruction algorithms, are essential for on-chip and implantable applications. Highly sensitive spectral measurement using a single detector allows the footprints of such spectrometers to be scaled down while achieving spectral resolution approaching that of benchtop systems. We report a high-performance computational spectrometer based on a single van der Waals junction with an electrically tunable transport-mediated spectral response. We achieve high peak wavelength accuracy (∼0.36 nanometers), high spectral resolution (∼3 nanometers), broad operation bandwidth (from ∼405 to 845 nanometers), and proof-of-concept spectral imaging. Our approach provides a route toward ultraminiaturization and offers unprecedented performance in accuracy, resolution, and operation bandwidth for single-detector computational spectrometers.
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Affiliation(s)
- Hoon Hahn Yoon
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Henry A Fernandez
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Fedor Nigmatulin
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Weiwei Cai
- Key Lab of Education Ministry for Power Machinery and Engineering, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zongyin Yang
- College of Information Science and Electronic Engineering and State Key Laboratory of Modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, China
| | - Hanxiao Cui
- School of Aeronautics and Astronautics, Sichuan University, Chengdu 610065, China
| | - Faisal Ahmed
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland
| | - Xiaoqi Cui
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Md Gius Uddin
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Ethan D Minot
- Department of Physics, Oregon State University, Corvallis, OR 97331, USA
| | - Harri Lipsanen
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland
| | - Kwanpyo Kim
- Department of Physics, Yonsei University, Seoul 03722, Republic of Korea
| | - Pertti Hakonen
- QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
| | - Tawfique Hasan
- Cambridge Graphene Centre, University of Cambridge, Cambridge CB3 0FA, UK
| | - Zhipei Sun
- Department of Electronics and Nanoengineering, Aalto University, Espoo 02150, Finland.,QTF Centre of Excellence, Department of Applied Physics, Aalto University, Aalto 00076, Finland
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97
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Xiong Y, Xu D, Feng Y, Zhang G, Lin P, Chen X. P-Type 2D Semiconductors for Future Electronics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2206939. [PMID: 36245325 DOI: 10.1002/adma.202206939] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 09/30/2022] [Indexed: 06/16/2023]
Abstract
2D semiconductors represent one of the best candidates to extend Moore's law for their superiorities, such as keeping high carrier mobility and remarkable gate-control capability at atomic thickness. Complementary transistors and van der Waals junctions are critical in realizing 2D semiconductors-based integrated circuits suitable for future electronics. N-type 2D semiconductors have been reported predominantly for the strong electron doping caused by interfacial charge impurities and internal structural defects. By contrast, superior and reliable p-type 2D semiconductors with holes as majority carriers are still scarce. Not only that, but some critical issues have not been adequately addressed, including their controlled synthesis in wafer size and high quality, defect and carrier modulation, optimization of interface and contact, and application in high-speed and low-power integrated devices. Here the material toolkit, synthesis strategies, device basics, and digital electronics closely related to p-type 2D semiconductors are reviewed. Their opportunities, challenges, and prospects for future electronic applications are also discussed, which would be promising or even shining in the post-Moore era.
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Affiliation(s)
- Yunhai Xiong
- MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Duo Xu
- MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Yiping Feng
- MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
| | - Guangjie Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing, 100190, China
| | - Pei Lin
- Key Laboratory of Materials Physics of Ministry of Education, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, 450001, China
| | - Xiang Chen
- MIIT Key Laboratory of Advanced Display Materials and Devices, School of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China
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98
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Wei T, Han Z, Zhong X, Xiao Q, Liu T, Xiang D. Two dimensional semiconducting materials for ultimately scaled transistors. iScience 2022; 25:105160. [PMID: 36204270 PMCID: PMC9529977 DOI: 10.1016/j.isci.2022.105160] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Two dimensional (2D) semiconductors have been established as promising candidates to break through the short channel effect that existed in Si metal-oxide-semiconductor field-effect-transistor (MOSFET), owing to their unique atomically layered structure and dangling-bond-free surface. The last decade has witnessed the significant progress in the size scaling of 2D transistors by various approaches, in which the physical gate length of the transistors has shrank from micrometer to sub-one nanometer with superior performance, illustrating their potential as a replacement technology for Si MOSFETs. Here, we review state-of-the-art techniques to achieve ultra-scaled 2D transistors with novel configurations through the scaling of channel, gate, and contact length. We provide comprehensive views of the merits and drawbacks of the ultra-scaled 2D transistors by summarizing the relevant fabrication processes with the corresponding critical parameters achieved. Finally, we identify the key opportunities and challenges for integrating ultra-scaled 2D transistors in the next-generation heterogeneous circuitry.
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Affiliation(s)
- Tianyao Wei
- Institute of Optoelectronics, Fudan University, Shanghai 200438, People’s Republic of China
- Frontier Institute of Chip and System, Fudan University, Shanghai 200438, People’s Republic of China
| | - Zichao Han
- Institute of Optoelectronics, Fudan University, Shanghai 200438, People’s Republic of China
| | - Xinyi Zhong
- Department of Materials Science, Fudan University, Shanghai 200433, People’s Republic of China
| | - Qingyu Xiao
- Department of Materials Science, Fudan University, Shanghai 200433, People’s Republic of China
| | - Tao Liu
- Institute of Optoelectronics, Fudan University, Shanghai 200438, People’s Republic of China
- Zhangjiang Fudan International Innovation Centre, Fudan University, Shanghai 200438, People’s Republic of China
- Corresponding author
| | - Du Xiang
- Frontier Institute of Chip and System, Fudan University, Shanghai 200438, People’s Republic of China
- Zhangjiang Fudan International Innovation Centre, Fudan University, Shanghai 200438, People’s Republic of China
- Shanghai Qi Zhi Institute, Shanghai 200232, People’s Republic of China
- Corresponding author
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99
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Han MJ, Kim M, Tsukruk VV. Multivalued Logic for Optical Computing with Photonically Enabled Chiral Bio-organic Structures. ACS NANO 2022; 16:13684-13694. [PMID: 35882006 DOI: 10.1021/acsnano.2c04182] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Photonic bio-organic multiphase structures are suggested here for integrated thin-film electronic nets with multilevel logic elements for multilevel computing via a reconfigurable photonic bandgap of chiral biomaterials. Herein, inspired by an artificial intelligence system with efficient information integration and computing capability, the photonically active dielectric layer of chiral nematic cellulose nanocrystals is combined with printed-in p- and n-type organic semiconductors as a bifunctional logical element. These adaptive logic elements are capable of triggering tailored quantized electrical output signals under light with different photon energy and at the different photonic bandgaps of the active dielectric layer. The bifunctional structures enable complex memory behavior upon repetitive changes of photonic bandgap (controlled by expansion/contraction of chiral nematic pitch) and photon energy (controlled by light absorption wavelength of complementary organic semiconductor layers), exhibiting effectively a reconfigurable ternary logic response. This proof-of-concept bio-assisted multivalued logic structure facilitates an optical computing system for low-power optical information processing integrated with human-machine interfaces.
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Affiliation(s)
- Moon Jong Han
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Minkyu Kim
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
| | - Vladimir V Tsukruk
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
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100
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Sun Z, Pang CS, Wu P, Hung TYT, Li MY, Liew SL, Cheng CC, Wang H, Wong HSP, Li LJ, Radu I, Chen Z, Appenzeller J. Statistical Assessment of High-Performance Scaled Double-Gate Transistors from Monolayer WS 2. ACS NANO 2022; 16:14942-14950. [PMID: 36094410 DOI: 10.1021/acsnano.2c05902] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Scaling of monolayer transition metal dichalcogenide (TMD) field-effect transistors (FETs) is an important step toward evaluating the application space of TMD materials. Although some work on ultrashort channel monolayer (ML) TMD FETs has been published, there exist no comprehensive studies that assess their performance in a statistically relevant manner, providing critical insights into the impact of the device geometry. Part of the reason for the absence of such a study is the substantial variability of TMD devices when processes are not carefully controlled. In this work, we show a statistical study of ultrashort channel double-gated ML WS2 FETs exhibiting excellent device performance and limited device-to-device variations. From a detailed analysis of cross-sectional scanning transmission electron microscopy (STEM) images and careful technology computer aided design (TCAD) simulations, we evaluated, in particular, an unexpected deterioration of the subthreshold characteristics for our shortest devices. Two potential candidates for the observed behavior were identified, i.e., buckling of the TMD on the substrate and loss of gate control due to the source geometry and the high-k dielectric between the metal gate and the metal source electrode.
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