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Kang M, Hong W, Lee I, Park S, Park C, Bae S, Lim H, Choi SY. Tunable Doping Strategy for Few-Layer MoS 2 Field-Effect Transistors via NH 3 Plasma Treatment. ACS APPLIED MATERIALS & INTERFACES 2024; 16:43849-43859. [PMID: 39135314 DOI: 10.1021/acsami.4c08549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/23/2024]
Abstract
Molybdenum disulfide (MoS2) is a promising candidate for next-generation transistor channel materials, boasting outstanding electrical properties and ultrathin structure. Conventional ion implantation processes are unsuitable for atomically thin two-dimensional (2D) materials, necessitating nondestructive doping methods. We proposed a novel approach: tunable n-type doping through sulfur vacancies (VS) and p-type doping by nitrogen substitution in MoS2, controlled by the duration of NH3 plasma treatment. Our results reveal that NH3 plasma exposure of 20 s increases the 2D sheet carrier density (n2D) in MoS2 field-effect transistors (FETs) by +4.92 × 1011 cm-2 at a gate bias of 0 V, attributable to sulfur vacancy generation. Conversely, treatment of 40 s reduces n2D by -3.71 × 1011 cm-2 due to increased nitrogen doping. X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence analyses corroborate these electrical characterization results, indicating successful n- and p-type doping. Temperature-dependent measurements show that the Schottky barrier height at the metal-semiconductor contact decreases by -31 meV under n-type conditions and increases by +37 meV for p-type doping. This study highlights NH3 plasma treatment as a viable doping method for 2D materials in electronic and optoelectronic device engineering.
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Affiliation(s)
- Mingu Kang
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Woonggi Hong
- School of Electronics and Electrical Engineering, Convergence Semiconductor Research Center, Dankook University, 152 Jukjeon-ro, Suji-gu, Yongin-si, Gyeonggi-do 16890, Republic of Korea
| | - Inseong Lee
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Seohak Park
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Cheolmin Park
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sanggeun Bae
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Hyeongjin Lim
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
| | - Sung-Yool Choi
- School of Electrical Engineering, Graduate School of Semiconductor Technology, Graphene/2D Materials Research Center, Center for Advanced Materials Discovery towards 3D Display, KAIST, Daehakro, Yuseong-gu, Daejeon 34141, Republic of Korea
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Mawlong LPL, Hoang AT, Chintalapalli J, Ji S, Lee K, Kim K, Ahn JH. Reduced Defect Density in MOCVD-Grown MoS 2 by Manipulating the Precursor Phase. ACS APPLIED MATERIALS & INTERFACES 2023; 15:47359-47367. [PMID: 37756669 DOI: 10.1021/acsami.3c09027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/29/2023]
Abstract
Advancements in the synthesis of large-area, high-quality two-dimensional transition metal dichalcogenides such as MoS2 play a crucial role in the development of future electronic and optoelectronic devices. The presence of defects formed by sulfur vacancies in MoS2 results in low photoluminescence emission and imparts high n-type doping behavior, thus substantially affecting material quality. Herein, we report a new method in which single-phase (liquid) precursors are used for the metal-organic chemical vapor deposition (MOCVD) growth of a MoS2 film. Furthermore, we fabricated a high-performance photodetector (PD) and achieved improved photoresponsivity and faster photoresponse in the spectral range 405-637 nm compared to those of PDs fabricated by the conventional MOCVD method. In addition, the fabricated MoS2 thin film showed a threshold voltage shift in the positive gate bias direction owing to the reduced number of S vacancy defects in the MoS2 lattice. Thus, our method significantly improved the synthesis of monolayer MoS2 and can expand the application scope of high-quality, atomically thin materials in large-scale electronic and optoelectronic devices.
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Affiliation(s)
- Larionette P L Mawlong
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Anh Tuan Hoang
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Jyothi Chintalapalli
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Seunghyeon Ji
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Kihyun Lee
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul 03722, Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Kwanpyo Kim
- Department of Physics, Yonsei University, 50 Yonsei-ro, Seoul 03722, Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), 50 Yonsei-ro, Seoul 03722, Republic of Korea
| | - Jong-Hyun Ahn
- School of Electrical and Electronic Engineering, Yonsei University, 50 Yonsei-ro, Seoul 03722, Republic of Korea
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Baek GW, Kim YJ, Lee M, Kwon Y, Chun B, Park G, Seo H, Yang H, Kwak J. Progress in the Development of Active-Matrix Quantum-Dot Light-Emitting Diodes Driven by Non-Si Thin-Film Transistors. MATERIALS (BASEL, SWITZERLAND) 2022; 15:ma15238511. [PMID: 36500003 PMCID: PMC9736594 DOI: 10.3390/ma15238511] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/18/2022] [Accepted: 11/27/2022] [Indexed: 05/28/2023]
Abstract
This paper aims to discuss the key accomplishments and further prospects of active-matrix (AM) quantum-dot (QD) light-emitting diodes (QLEDs) display. We present an overview and state-of-the-art of QLEDs as a frontplane and non-Si-based thin-film transistors (TFTs) as a backplane to meet the requirements for the next-generation displays, such as flexibility, transparency, low power consumption, fast response, high efficiency, and operational reliability. After a brief introduction, we first review the research on non-Si-based TFTs using metal oxides, transition metal dichalcogenides, and semiconducting carbon nanotubes as the driving unit of display devices. Next, QLED technologies are analyzed in terms of the device structure, device engineering, and QD patterning technique to realize high-performance, full-color AM-QLEDs. Lastly, recent research on the monolithic integration of TFT-QLED is examined, which proposes a new perspective on the integrated device. We anticipate that this review will help the readership understand the fundamentals, current state, and issues on TFTs and QLEDs for future AM-QLED displays.
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Affiliation(s)
- Geun Woo Baek
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeon Jun Kim
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Minhyung Lee
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Yeunwoo Kwon
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Beomsoo Chun
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Ganghyun Park
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Hansol Seo
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Heesun Yang
- Department of Materials Science and Engineering, Hongik University, Seoul 04066, Republic of Korea
| | - Jeonghun Kwak
- Department of Electrical and Computer Engineering, Inter-University Semiconductor Research Center, Soft Foundry Institute, Seoul National University, Seoul 08826, Republic of Korea
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Optical and Material Characteristics of MoS 2/Cu 2O Sensor for Detection of Lung Cancer Cell Types in Hydroplegia. Int J Mol Sci 2022; 23:ijms23094745. [PMID: 35563136 PMCID: PMC9101548 DOI: 10.3390/ijms23094745] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 02/07/2023] Open
Abstract
In this study, n-type MoS2 monolayer flakes are grown through chemical vapor deposition (CVD), and a p-type Cu2O thin film is grown via electrochemical deposition. The crystal structure of the grown MoS2 flakes is analyzed through transmission electron microscopy. The monolayer structure of the MoS2 flakes is verified with Raman spectroscopy, multiphoton excitation microscopy, atomic force microscopy, and photoluminescence (PL) measurements. After the preliminary processing of the grown MoS2 flakes, the sample is then transferred onto a Cu2O thin film to complete a p-n heterogeneous structure. Data are confirmed via scanning electron microscopy, SHG, and Raman mapping measurements. The luminous energy gap between the two materials is examined through PL measurements. Results reveal that the thickness of the single-layer MoS2 film is 0.7 nm. PL mapping shows a micro signal generated at the 627 nm wavelength, which belongs to the B2 excitons of MoS2 and tends to increase gradually when it approaches 670 nm. Finally, the biosensor is used to detect lung cancer cell types in hydroplegia significantly reducing the current busy procedures and longer waiting time for detection. The results suggest that the fabricated sensor is highly sensitive to the change in the photocurrent with the number of each cell, the linear regression of the three cell types is as high as 99%. By measuring the slope of the photocurrent, we can identify the type of cells and the number of cells.
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Han B, Zhao Y, Ma C, Wang C, Tian X, Wang Y, Hu W, Samorì P. Asymmetric Chemical Functionalization of Top-Contact Electrodes: Tuning the Charge Injection for High-Performance MoS 2 Field-Effect Transistors and Schottky Diodes. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2109445. [PMID: 35061928 DOI: 10.1002/adma.202109445] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The fabrication of high-performance (opto-)electronic devices based on 2D channel materials requires the optimization of the charge injection at electrode-semiconductor interfaces. While chemical functionalization with chemisorbed self-assembled monolayers has been extensively exploited to adjust the work function of metallic electrodes in bottom-contact devices, such a strategy has not been demonstrated for the top-contact configuration, despite the latter being known to offer enhanced charge-injection characteristics. Here, a novel contact engineering method is developed to functionalize gold electrodes in top-contact field-effect transistors (FETs) via the transfer of chemically pre-modified electrodes. The source and drain Au electrodes of the molybdenum disulfide (MoS2 ) FETs are functionalized with thiolated molecules possessing different dipole moments. While the modification of the electrodes with electron-donating molecules yields a marked improvement of device performance, the asymmetric functionalization of the source and drain electrodes with different molecules with opposed dipole moment enables the fabrication of a high-performance Schottky diode with a rectification ratio of ≈103 . This unprecedented strategy to tune the charge injection in top-contact MoS2 FETs is of general applicability for the fabrication of high-performance (opto-)electronic devices, in which asymmetric charge injection is required, enabling tailoring of the device characteristics on demand.
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Affiliation(s)
- Bin Han
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
| | - Yuda Zhao
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
| | - Chun Ma
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
| | - Can Wang
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
| | - Xinzi Tian
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - Ye Wang
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
| | - Wenping Hu
- Tianjin Key Laboratory of Molecular Optoelectronic Sciences, Department of Chemistry, School of Science, Tianjin University & Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072, China
| | - Paolo Samorì
- Université de Strasbourg, CNRS, ISIS, 8 allée Gaspard Monge, Strasbourg, 67000, France
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Growth Mechanism of Periodic-Structured MoS 2 by Transmission Electron Microscopy. NANOMATERIALS 2021; 12:nano12010135. [PMID: 35010085 PMCID: PMC8796029 DOI: 10.3390/nano12010135] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 12/17/2021] [Accepted: 12/30/2021] [Indexed: 12/28/2022]
Abstract
Molybdenum disulfide (MoS2) was grown on a laser-processed periodic-hole sapphire substrate through chemical vapor deposition. The main purpose was to investigate the mechanism of MoS2 growth in substrate with a periodic structure. By controlling the amount and position of the precursor, adjusting the growth temperature and time, and setting the flow rate of argon gas, MoS2 grew in the region of the periodic holes. A series of various growth layer analyses of MoS2 were then confirmed by Raman spectroscopy, photoluminescence spectroscopy, and atomic force microscopy. Finally, the growth mechanism was studied by transmission electron microscopy (TEM). The experimental results show that in the appropriate environment, MoS2 can be successfully grown on substrate with periodic holes, and the number of growth layers can be determined through measurements. By observing the growth mechanism, composition analysis, and selected area electron diffraction diagram by TEM, we comprehensively understand the growth phenomenon. The results of this research can serve as a reference for the large-scale periodic growth of MoS2. The production of periodic structures by laser drilling is advantageous, as it is relatively simpler than other methods.
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Seo SG, Ryu JH, Kim SY, Jeong J, Jin SH. Enhancement of Photodetective Properties on Multilayered MoS 2 Thin Film Transistors via Self-Assembled Poly-L-Lysine Treatment and Their Potential Application in Optical Sensors. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:1586. [PMID: 34204218 PMCID: PMC8234691 DOI: 10.3390/nano11061586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/07/2021] [Accepted: 06/10/2021] [Indexed: 01/04/2023]
Abstract
Photodetectors and display backplane transistors based on molybdenum disulfide (MoS2) have been regarded as promising topics. However, most studies have focused on the improvement in the performances of the MoS2 photodetector itself or emerging applications. In this study, to suggest a better insight into the photodetector performances of MoS2 thin film transistors (TFTs), as photosensors for possible integrated system, we performed a comparative study on the photoresponse of MoS2 and hydrogenated amorphous silicon (a-Si:H) TFTs. As a result, in the various wavelengths and optical power ranges, MoS2 TFTs exhibit 2~4 orders larger photo responsivities and detectivities. The overall quantitative comparison of photoresponse in single device and inverters confirms a much better performance by the MoS2 photodetectors. Furthermore, as a strategy to improve the field effect mobility and photoresponse of the MoS2 TFTs, molecular doping via poly-L-lysine (PLL) treatment was applied to the MoS2 TFTs. Transfer and output characteristics of the MoS2 TFTs clearly show improved photocurrent generation under a wide range of illuminations (740~365 nm). These results provide useful insights for considering MoS2 as a next-generation photodetector in flat panel displays and makes it more attractive due to the fact of its potential as a high-performance photodetector enabled by a novel doping technique.
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Affiliation(s)
| | | | | | | | - Sung Hun Jin
- Department of Electronic Engineering, Incheon National University, Incheon 22012, Korea; (S.G.S.); (J.H.R.); (S.Y.K.); (J.J.)
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Li KC, Lu MY, Nguyen HT, Feng SW, Artemkina SB, Fedorov VE, Wang HC. Intelligent Identification of MoS 2 Nanostructures with Hyperspectral Imaging by 3D-CNN. NANOMATERIALS 2020; 10:nano10061161. [PMID: 32545726 PMCID: PMC7353172 DOI: 10.3390/nano10061161] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023]
Abstract
Increasing attention has been paid to two-dimensional (2D) materials because of their superior performance and wafer-level synthesis methods. However, the large-area characterization, precision, intelligent automation, and high-efficiency detection of nanostructures for 2D materials have not yet reached an industrial level. Therefore, we use big data analysis and deep learning methods to develop a set of visible-light hyperspectral imaging technologies successfully for the automatic identification of few-layers MoS2. For the classification algorithm, we propose deep neural network, one-dimensional (1D) convolutional neural network, and three-dimensional (3D) convolutional neural network (3D-CNN) models to explore the correlation between the accuracy of model recognition and the optical characteristics of few-layers MoS2. The experimental results show that the 3D-CNN has better generalization capability than other classification models, and this model is applicable to the feature input of the spatial and spectral domains. Such a difference consists in previous versions of the present study without specific substrate, and images of different dynamic ranges on a section of the sample may be administered via the automatic shutter aperture. Therefore, adjusting the imaging quality under the same color contrast conditions is unnecessary, and the process of the conventional image is not used to achieve the maximum field of view recognition range of ~1.92 mm2. The image resolution can reach ~100 nm and the detection time is 3 min per one image.
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Affiliation(s)
- Kai-Chun Li
- Department of Mechanical Engineering and Advanced Institute of Manufacturing with High Tech Innovations, National Chung Cheng University, 168, University Rd., Min Hsiung, Chia Yi 62102, Taiwan; (K.-C.L.); (H.T.N.)
| | - Ming-Yen Lu
- Department of Materials Science and Engineering, National Tsing Hua University, 101, Sec. 2, Kuang-Fu Road, Hsinchu 30013, Taiwan;
| | - Hong Thai Nguyen
- Department of Mechanical Engineering and Advanced Institute of Manufacturing with High Tech Innovations, National Chung Cheng University, 168, University Rd., Min Hsiung, Chia Yi 62102, Taiwan; (K.-C.L.); (H.T.N.)
| | - Shih-Wei Feng
- Department of Applied Physics, National University of Kaohsiung, 700 Kaohsiung University Rd., Nanzih District, Kaohsiung 81148, Taiwan;
| | - Sofya B. Artemkina
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.B.A.); (V.E.F.)
- Department of Natural Sciences, Novosibirsk State University, 1, Pirogova str., 630090 Novosibirsk, Russia
| | - Vladimir E. Fedorov
- Nikolaev Institute of Inorganic Chemistry, Siberian Branch of Russian Academy of Sciences, 630090 Novosibirsk, Russia; (S.B.A.); (V.E.F.)
- Department of Natural Sciences, Novosibirsk State University, 1, Pirogova str., 630090 Novosibirsk, Russia
| | - Hsiang-Chen Wang
- Department of Mechanical Engineering and Advanced Institute of Manufacturing with High Tech Innovations, National Chung Cheng University, 168, University Rd., Min Hsiung, Chia Yi 62102, Taiwan; (K.-C.L.); (H.T.N.)
- Correspondence:
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