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Yang S, Liu K, Xu Y, Liu L, Li H, Zhai T. Gate Dielectrics Integration for 2D Electronics: Challenges, Advances, and Outlook. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207901. [PMID: 36226584 DOI: 10.1002/adma.202207901] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/28/2022] [Indexed: 05/05/2023]
Abstract
2D semiconductors have emerged both as an ideal platform for fundamental studies and as promising channel materials in beyond-silicon field-effect-transistors due to their outstanding electrical properties and exceptional tunability via external field. However, the lack of proper dielectrics for 2D semiconductors has become a major roadblock for their further development toward practical applications. The prominent issues between conventional 3D dielectrics and 2D semiconductors arise from the integration and interface quality, where defect states and imperfections lead to dramatic deterioration of device performance. In this review article, the root causes of such issues are briefly analyzed and recent advances on some possible solutions, including various approaches of adapting conventional dielectrics to 2D semiconductors, and the development of novel dielectrics with van der Waals surface toward high-performance 2D electronics are summarized. Then, in the perspective, the requirements of ideal dielectrics for state-of-the-art 2D devices are outlined and an outlook for their future development is provided.
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Affiliation(s)
- Sijie Yang
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Kailang Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Yongshan Xu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Lixin Liu
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Huiqiao Li
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
| | - Tianyou Zhai
- State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China
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Yoon Y, Koo JY, Oh J, Kim S, Choi HC, Yoon SM. Surface-guided polymorphism control of titanyl phthalocyanine single crystals. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00228c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Polymorphism control of the titanyl-phthalocyanine (TiOPc) single crystals by molecule-surface interactions and their effects of crystallographic structural differences on photo-electronics.
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Affiliation(s)
- Youngkwan Yoon
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- Republic of Korea
| | - Jin Young Koo
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- Republic of Korea
| | - Jongwon Oh
- Department of Chemistry
- Wonkwang University
- Iksan 54538
- Republic of Korea
| | - Soyoung Kim
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- Republic of Korea
| | - Hee Cheul Choi
- Department of Chemistry
- Pohang University of Science and Technology (POSTECH)
- Pohang 37673
- Republic of Korea
| | - Seok Min Yoon
- Department of Chemistry
- Wonkwang University
- Iksan 54538
- Republic of Korea
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Ahn H, Huang YC, Lin CW, Chiu YL, Lin EC, Lai YY, Lee YH. Efficient Defect Healing of Transition Metal Dichalcogenides by Metallophthalocyanine. ACS APPLIED MATERIALS & INTERFACES 2018; 10:29145-29152. [PMID: 30044602 DOI: 10.1021/acsami.8b09378] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted great attention as alternatives to graphene with semiconducting band gaps. Mono- or few-layer TMDCs can be prepared by various methods, but regardless of the fabrication methods [such as mechanical exfoliation and chemical vapor deposition (CVD)], TMDCs contain many structural defects, which significantly affect their physical properties and limit their performance in applications. Metallophthalocyanines (MPcs) are organic semiconductors, and as dopants, they are capable of modulating the optical and electrical properties of other semiconducting materials. Here, we report that besides the ability to modulate the optoelectronic properties of 2D TMDCs, MPc molecules can be used to heal defects and improve the physicochemical properties of TMDCs. Doping of planar MPc molecules to TMDCs is achieved by a simple solution dip-coating method and results in a significant improvement in the optical properties and thermal responses of CVD-grown TMDCs, even comparable to those of mechanically exfoliated counterparts. Study of carrier dynamics shows that the adsorption of MPc on the TMDC surface leads to the complete suppression of the mid-gap defect-induced absorption in TMDCs. Furthermore, MPc molecules with a large lateral size are found to effectively reduce the point defects in mechanically exfoliated TMDCs introduced during the preparation process. Our results not only clarify the optoelectronic modulation mechanism of chemical doping but also offer a simple method to control the nanosized defects in 2D TMDCs.
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Affiliation(s)
- Hyeyoung Ahn
- Department of Photonics , National Chiao Tung University , Hsinchu 30010 , Taiwan
| | - Yu-Chiao Huang
- Department of Photonics , National Chiao Tung University , Hsinchu 30010 , Taiwan
| | - Chang-Wei Lin
- Department of Photonics , National Chiao Tung University , Hsinchu 30010 , Taiwan
| | - Yi-Lun Chiu
- Department of Photonics , National Chiao Tung University , Hsinchu 30010 , Taiwan
| | - Erh-Chen Lin
- Institute of NanoEngineering and MicroSystems , National Tsing-Hua University , Hsinchu 30010 , Taiwan
| | - Ying-Yu Lai
- Institute of NanoEngineering and MicroSystems , National Tsing-Hua University , Hsinchu 30010 , Taiwan
| | - Yi-Hsien Lee
- Institute of NanoEngineering and MicroSystems , National Tsing-Hua University , Hsinchu 30010 , Taiwan
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Progress in Contact, Doping and Mobility Engineering of MoS2: An Atomically Thin 2D Semiconductor. CRYSTALS 2018. [DOI: 10.3390/cryst8080316] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Atomically thin molybdenum disulfide (MoS2), a member of the transition metal dichalcogenide (TMDC) family, has emerged as the prototypical two-dimensional (2D) semiconductor with a multitude of interesting properties and promising device applications spanning all realms of electronics and optoelectronics. While possessing inherent advantages over conventional bulk semiconducting materials (such as Si, Ge and III-Vs) in terms of enabling ultra-short channel and, thus, energy efficient field-effect transistors (FETs), the mechanically flexible and transparent nature of MoS2 makes it even more attractive for use in ubiquitous flexible and transparent electronic systems. However, before the fascinating properties of MoS2 can be effectively harnessed and put to good use in practical and commercial applications, several important technological roadblocks pertaining to its contact, doping and mobility (µ) engineering must be overcome. This paper reviews the important technologically relevant properties of semiconducting 2D TMDCs followed by a discussion of the performance projections of, and the major engineering challenges that confront, 2D MoS2-based devices. Finally, this review provides a comprehensive overview of the various engineering solutions employed, thus far, to address the all-important issues of contact resistance (RC), controllable and area-selective doping, and charge carrier mobility enhancement in these devices. Several key experimental and theoretical results are cited to supplement the discussions and provide further insight.
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Cheng L, Lee J, Zhu H, Ravichandran AV, Wang Q, Lucero AT, Kim MJ, Wallace RM, Colombo L, Kim J. Sub-10 nm Tunable Hybrid Dielectric Engineering on MoS 2 for Two-Dimensional Material-Based Devices. ACS NANO 2017; 11:10243-10252. [PMID: 28832118 DOI: 10.1021/acsnano.7b04813] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The successful realization of high-performance 2D-materials-based nanoelectronics requires integration of high-quality dielectric films as a gate insulator. In this work, we explore the integration of organic and inorganic hybrid dielectrics on MoS2 and study the chemical and electrical properties of these hybrid films. Our atomic force microscopy, X-ray photoelectron spectroscopy (XPS), Raman, and photoluminescence results show that, aside from the excellent film uniformity and thickness scalability down to 2.5 nm, the molecular layer deposition of octenyltrichlorosilane (OTS) and Al2O3 hybrid films preserves the chemical and structural integrity of the MoS2 surface. The XPS band alignment analysis and electrical characterization reveal that through the inclusion of an organic layer in the dielectric film, the band gap and dielectric constant can be tuned from ∼7.00 to 6.09 eV and ∼9.0 to 4.5, respectively. Furthermore, the hybrid films show promising dielectric properties, including a high breakdown field of ∼7.8 MV/cm, a low leakage current density of ∼1 × 10-6 A/cm2 at 1 MV/cm, a small hysteresis of ∼50 mV, and a top-gate subthreshold voltage swing of ∼79 mV/dec. Our experimental findings provide a facile way of fabricating scalable hybrid gate dielectrics on transition metal dichalcogenides for 2D-material-based flexible electronics applications.
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Affiliation(s)
- Lanxia Cheng
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Jaebeom Lee
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Hui Zhu
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Arul Vigneswar Ravichandran
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Qingxiao Wang
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Antonio T Lucero
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
| | - Moon J Kim
- 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
| | - Luigi Colombo
- Texas Instruments , Dallas, Texas 75243, United States
| | - Jiyoung Kim
- Department of Materials Science and Engineering, The University of Texas at Dallas , Richardson, Texas 75080, United States
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Quinn T, Choudhury P. Direct oxidation of methane to methanol on single-site copper-oxo species of copper porphyrin functionalized graphene: A DFT study. MOLECULAR CATALYSIS 2017. [DOI: 10.1016/j.mcat.2017.01.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Zhang H, Chiappe D, Meersschaut J, Conard T, Franquet A, Nuytten T, Mannarino M, Radu I, Vandervorst W, Delabie A. Nucleation and growth mechanisms of Al2O3 atomic layer deposition on synthetic polycrystalline MoS2. J Chem Phys 2017; 146:052810. [DOI: 10.1063/1.4967406] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- H. Zhang
- Department of Chemistry, KU Leuven, Leuven 3001, Belgium
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - D. Chiappe
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | | | - T. Conard
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | | | - T. Nuytten
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - M. Mannarino
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - I. Radu
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
| | - W. Vandervorst
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
- Department of Physics and Astronomy, KU Leuven, Leuven 3001, Belgium
| | - A. Delabie
- Department of Chemistry, KU Leuven, Leuven 3001, Belgium
- IMEC, Kapeldreef 75, 3001 Leuven, Belgium
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Park JH, Fathipour S, Kwak I, Sardashti K, Ahles CF, Wolf SF, Edmonds M, Vishwanath S, Xing HG, Fullerton-Shirey SK, Seabaugh A, Kummel AC. Atomic Layer Deposition of Al2O3 on WSe2 Functionalized by Titanyl Phthalocyanine. ACS NANO 2016; 10:6888-6896. [PMID: 27305595 DOI: 10.1021/acsnano.6b02648] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
To deposit an ultrathin dielectric onto WSe2, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al2O3 on WSe2. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H2O nucleate on the TiOPc, resulting in a uniform deposition of Al2O3, as confirmed by atomic force microscopy and cross-sectional transmission electron microscopy. The field-effect transistors (FETs) formed using this process have a leakage current of 0.046 pA/μm(2) at 1 V gate bias with 3.0 nm equivalent oxide thickness, which is a lower leakage current than prior reports. The n-branch of the FET yielded a subthreshold swing of 80 mV/decade.
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Affiliation(s)
| | - Sara Fathipour
- Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | | | | | | | | | | | - Suresh Vishwanath
- Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Huili Grace Xing
- Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
| | - Susan K Fullerton-Shirey
- Department of Chemical and Petroleum Engineering, University of Pittsburgh , Pittsburgh, Pennsylvania 15213, United States
| | - Alan Seabaugh
- Department of Electrical Engineering, University of Notre Dame , Notre Dame, Indiana 46556, United States
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