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Li K, Han X, Meng Y, Li J, Hong Y, Chen X, You JY, Yao L, Hu W, Xia Z, Ke G, Zhang L, Zhang J, Zhao X. Single-Image-Based Deep Learning for Precise Atomic Defect Identification. NANO LETTERS 2024; 24:10275-10283. [PMID: 39106329 DOI: 10.1021/acs.nanolett.4c02654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/09/2024]
Abstract
Defect engineering is widely used to impart the desired functionalities on materials. Despite the widespread application of atomic-resolution scanning transmission electron microscopy (STEM), traditional methods for defect analysis are highly sensitive to random noise and human bias. While deep learning (DL) presents a viable alternative, it requires extensive amounts of training data with labeled ground truth. Herein, employing cycle generative adversarial networks (CycleGAN) and U-Nets, we propose a method based on a single experimental STEM image to tackle high annotation costs and image noise for defect detection. Not only atomic defects but also oxygen dopants in monolayer MoS2 are visualized. The method can be readily extended to other two-dimensional systems, as the training is based on unit-cell-level images. Therefore, our results outline novel ways to train the model with minimal data sets, offering great opportunities to fully exploit the power of DL in the materials science community.
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Affiliation(s)
- Kangshu Li
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Xiaocang Han
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Yuan Meng
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Junxian Li
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | | | - Xiang Chen
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Jing-Yang You
- Department of Physics, National University of Singapore, Singapore 117551
| | - Lin Yao
- DP Technology, Beijing 100080, China
| | - Wenchao Hu
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Zhiyi Xia
- DP Technology, Beijing 100080, China
| | - Guolin Ke
- DP Technology, Beijing 100080, China
| | - Linfeng Zhang
- DP Technology, Beijing 100080, China
- AI for Science Institute, Beijing 100084, China
| | - Jin Zhang
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
| | - Xiaoxu Zhao
- School of Materials Science and Engineering, Peking University, Beijing 100871, China
- AI for Science Institute, Beijing 100084, China
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2
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Ahn H, Moon G, Jung HG, Deng B, Yang DH, Yang S, Han C, Cho H, Yeo Y, Kim CJ, Yang CH, Kim J, Choi SY, Park H, Jeon J, Park JH, Jo MH. Integrated 1D epitaxial mirror twin boundaries for ultrascaled 2D MoS 2 field-effect transistors. NATURE NANOTECHNOLOGY 2024; 19:955-961. [PMID: 38961247 DOI: 10.1038/s41565-024-01706-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 05/29/2024] [Indexed: 07/05/2024]
Abstract
In atomically thin van der Waals materials, grain boundaries-the line defects between adjacent crystal grains with tilted in-plane rotations-are omnipresent. When the tilting angles are arbitrary, the grain boundaries form inhomogeneous sublattices, giving rise to local electronic states that are not controlled. Here we report on epitaxial realizations of deterministic MoS2 mirror twin boundaries (MTBs) at which two adjoining crystals are reflection mirroring by an exactly 60° rotation by position-controlled epitaxy. We showed that these epitaxial MTBs are one-dimensionally metallic to a circuit length scale. By utilizing the ultimate one-dimensional (1D) feature (width ~0.4 nm and length up to a few tens of micrometres), we incorporated the epitaxial MTBs as a 1D gate to build integrated two-dimensional field-effect transistors (FETs). The critical role of the 1D MTB gate was verified to scale the depletion channel length down to 3.9 nm, resulting in a substantially lowered channel off-current at lower gate voltages. With that, in both individual and array FETs, we demonstrated state-of-the-art performances for low-power logics. The 1D epitaxial MTB gates in this work suggest a novel synthetic pathway for the integration of two-dimensional FETs-that are immune to high gate capacitance-towards ultimate scaling.
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Affiliation(s)
- Heonsu Ahn
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Gunho Moon
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Hang-Gyo Jung
- Department of Semiconductor Convergence Engineering, Sungkyunkwan University, Suwon, Korea
| | - Bingchen Deng
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Dong-Hwan Yang
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Sera Yang
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Cheolhee Han
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Hyunje Cho
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Youngki Yeo
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Cheol-Joo Kim
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Chemical Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Chan-Ho Yang
- Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, Korea
| | - Jonghwan Kim
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Si-Young Choi
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea
| | - Hongkun Park
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, USA
- Department of Physics, Harvard University, Cambridge, MA, USA
| | - Jongwook Jeon
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Korea
| | - Jin-Hong Park
- Department of Semiconductor Convergence Engineering, Sungkyunkwan University, Suwon, Korea
- Department of Electrical and Computer Engineering, Sungkyunkwan University, Suwon, Korea
| | - Moon-Ho Jo
- Center for Van der Waals Quantum Solids, Institute for Basic Science, Pohang, Korea.
- Department of Materials Science and Engineering, Pohang University of Science and Technology, Pohang, Korea.
- Department of Physics, Pohang University of Science and Technology, Pohang, Korea.
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3
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Li Z, Bretscher H, Rao A. Chemical passivation of 2D transition metal dichalcogenides: strategies, mechanisms, and prospects for optoelectronic applications. NANOSCALE 2024; 16:9728-9741. [PMID: 38700268 DOI: 10.1039/d3nr06296a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
The interest in obtaining high-quality monolayer transition metal dichalcogenides (TMDs) for optoelectronic device applications has been growing dramatically. However, the prevalence of defects and unwanted doping in these materials remain challenges, as they both limit optical properties and device performance. Surface chemical treatments of monolayer TMDs have been effective in improving their photoluminescence yield and charge transport properties. In this scenario, a systematic understanding of the underlying mechanism of chemical treatments will lead to a rational design of passivation strategies in future research, ultimately taking a step toward practical optoelectronic applications. We will therefore describe in this mini-review the strategies, progress, mechanisms, and prospects of chemical treatments to passivate and improve the optoelectronic properties of TMDs.
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Affiliation(s)
- Zhaojun Li
- Solid State Physics, Department of Materials Science and Engineering, Uppsala University, 75103 Uppsala, Sweden.
| | - Hope Bretscher
- The Max Planck Institute for the Structure and Dynamics of Matter, 22761, Hamburg, Germany
| | - Akshay Rao
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, CB3 0HE, Cambridge, UK
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4
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Sun L, Zhao S, Tang X, Yu Q, Gao F, Liu J, Wang Y, Zhou Y, Yi H. Recent advances in catalytic oxidation of VOCs by two-dimensional ultra-thin nanomaterials. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 920:170748. [PMID: 38340848 DOI: 10.1016/j.scitotenv.2024.170748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/24/2024] [Accepted: 02/04/2024] [Indexed: 02/12/2024]
Abstract
Catalytic oxidation, an end-of-pipe treatment technology for effectively purifying volatile organic compounds (VOCs), has received widespread attention. The crux of catalytic oxidation lies in the development of efficient catalysts, with their optimization necessitating a comprehensive analysis of the catalytic reaction mechanism. Two-dimensional (2D) ultra-thin nanomaterials offer significant advantages in exploring the catalytic oxidation mechanism of VOCs due to their unique structure and properties. This review classifies strategies for regulating catalytic properties and typical applications of 2D materials in VOCs catalytic oxidation, in addition to their characteristics and typical characterization techniques. Furthermore, the possible reaction mechanism of 2D Co-based and Mn-based oxides in the catalytic oxidation of VOCs is analyzed, with a special focus on the synergistic effect between oxygen and metal vacancies. The objective of this review is to provide valuable references for scholars in the field.
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Affiliation(s)
- Long Sun
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Shunzheng Zhao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Xiaolong Tang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China
| | - Qingjun Yu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Fengyu Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Jun Liu
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Ya Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Yuansong Zhou
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China
| | - Honghong Yi
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing 100083, China; Beijing Key Laboratory of Resource-oriented Treatment of Industrial Pollutants, Beijing 100083, China.
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5
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Okello ON, Yang DH, Seo SY, Park J, Moon G, Shin D, Chu YS, Yang S, Mizoguchi T, Jo MH, Choi SY. Atomistic Probing of Defect-Engineered 2H-MoTe 2 Monolayers. ACS NANO 2024; 18:6927-6935. [PMID: 38374663 PMCID: PMC10919086 DOI: 10.1021/acsnano.3c08606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 02/21/2024]
Abstract
Point defects dictate various physical, chemical, and optoelectronic properties of two-dimensional (2D) materials, and therefore, a rudimentary understanding of the formation and spatial distribution of point defects is a key to advancement in 2D material-based nanotechnology. In this work, we performed the demonstration to directly probe the point defects in 2H-MoTe2 monolayers that are tactically exposed to (i) 200 °C-vacuum-annealing and (ii) 532 nm-laser-illumination; and accordingly, we utilize a deep learning algorithm to classify and quantify the generated point defects. We discovered that tellurium-related defects are mainly generated in both 2H-MoTe2 samples; but interestingly, 200 °C-vacuum-annealing and 532 nm-laser-illumination modulate a strong n-type and strong p-type 2H-MoTe2, respectively. While 200 °C-vacuum-annealing generates tellurium vacancies or tellurium adatoms, 532 nm-laser-illumination prompts oxygen atoms to be adsorbed/chemisorbed at tellurium vacancies, giving rise to the p-type characteristic. This work significantly advances the current understanding of point defect engineering in 2H-MoTe2 monolayers and other 2D materials, which is critical for developing nanoscale devices with desired functionality.
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Affiliation(s)
- Odongo
Francis Ngome Okello
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Samsung
Electronics, Foundry Analysis & Engineering Team, Global Manufacturing & Infra Technology, Samsungjeonja-ro 1, Hwaseong-si 18448, Republic
of Korea
| | - Dong-Hwan Yang
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Center
for Van der Waals Quantum Solids, Institute
of Basic Science (IBS), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
| | - Seung-Young Seo
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
| | - Jewook Park
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Center
for Van der Waals Quantum Solids, Institute
of Basic Science (IBS), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
| | - Gunho Moon
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Center
for Van der Waals Quantum Solids, Institute
of Basic Science (IBS), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
| | - Dongwon Shin
- Materials
Science and Technology Division, Oak Ridge
National Laboratory (ORNL), Oak Ridge, Tennessee 37831, United States
| | - Yu-Seong Chu
- Division
of Biomedical Engineering, College of Health Sciences, Yonsei University, 1, Yeonsedae-gil, Heungeop-myeon, Wonju-si 26493, Republic of Korea
| | - Sejung Yang
- Department
of Precision Medicine, Yonsei University,
Wonju College of Medicine, 20 Ilsan-ro, Wonju-si 26426, Republic of Korea
- Department
of Medical Informatics and Biostatistics, Graduate School, Yonsei University, 20 Ilsan-ro, Wonju-si 26426, Republic
of Korea
| | - Teruyasu Mizoguchi
- Institute
of Industrial Science, The University of
Tokyo, Komaba, Meguro 4-6-1, Tokyo 153-8505, Japan
| | - Moon-Ho Jo
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Center
for Van der Waals Quantum Solids, Institute
of Basic Science (IBS), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
| | - Si-Young Choi
- Department
of Materials Science and Engineering, Pohang
University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Center
for Van der Waals Quantum Solids, Institute
of Basic Science (IBS), 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
- Department
of Semiconductor Engineering, POSTECH, 77 Cheongam-ro, Nam-gu, Pohang-si 37673, Republic of Korea
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6
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Zhou H, Gao L, He S, Zhang Y, Geng J, Lu J, Cai J. Effects of strain and thickness on the mechanical, electronic, and optical properties of Cu 2Te. Phys Chem Chem Phys 2024; 26:5429-5437. [PMID: 38275021 DOI: 10.1039/d3cp04356h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2024]
Abstract
Two-dimensional transition-metal chalcogenides (TMCs) have attracted considerable attention because of their exceptional photoelectric properties, finding applications in diverse fields such as photovoltaics, lithium-ion batteries, catalysis, and energy conversion and storage. Recently, experimentally fabricated monolayers of semiconducting Cu2Te have emerged as intriguing materials with outstanding thermal and photoelectric characteristics. In this study, we employ first-principles calculations to investigate the mechanical, electronic, and optical properties of monolayer Cu2Te exhibiting both λ and ζ structures, considering the effects of thickness and strain. The calculations reveal the robust mechanical stability of λ-Cu2Te and ζ-Cu2Te under varying thickness and strain conditions. By applying -5% to +5% strain, the band gaps can be modulated, with ζ-Cu2Te exhibiting an indirect-to-direct transition at a biaxial strain of +5%. In addition, a semiconductor-to-metal transition is observed for both ζ-Cu2Te and λ-Cu2Te with increasing thickness. The absorption spectra of λ-Cu2Te and ζ-Cu2Te exhibit a redshift with an increase in the number of layers. These computational insights into Cu2Te provide valuable information for potential applications in nano-electromechanical systems, optoelectronics, and photocatalytic devices and may guide subsequent experimental research efforts.
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Affiliation(s)
- Hangjing Zhou
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Lei Gao
- Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China.
| | - Shihao He
- Faculty of Science, Kunming University of Science and Technology, Kunming 650500, China.
| | - Yong Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Jianqun Geng
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Jianchen Lu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Jinming Cai
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093, China.
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7
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Bianchi MG, Risplendi F, Re Fiorentin M, Cicero G. Engineering the Electrical and Optical Properties of WS 2 Monolayers via Defect Control. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2305162. [PMID: 38009517 PMCID: PMC10811516 DOI: 10.1002/advs.202305162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 09/25/2023] [Indexed: 11/29/2023]
Abstract
Two-dimensional (2D) materials as tungsten disulphide (WS2 ) are rising as the ideal platform for the next generation of nanoscale devices due to the excellent electric-transport and optical properties. However, the presence of defects in the as grown samples represents one of the main limiting factors for commercial applications. At the same time, WS2 properties are frequently tailored by introducing impurities at specific sites. Aim of this review paper is to present a complete description and discussion of the effects of both intentional and unintentional defects in WS2 , by an in depth analysis of the recent experimental and theoretical investigations reported in the literature. First, the most frequent intrinsic defects in WS2 are presented and their effects in the readily synthetized material are discussed. Possible solutions to remove and heal unintentional defects are also analyzed. Following, different doping schemes are reported, including the traditional substitution approach and innovative techniques based on the surface charge transfer with adsorbed atoms or molecules. The plethora of WS2 monolayer modifications presented in this review and the systematic analysis of the corresponding optical and electronic properties, represent strategic degrees of freedom the researchers may exploit to tailor WS2 optical and electronic properties for specific device applications.
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Affiliation(s)
- Michele Giovanni Bianchi
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Francesca Risplendi
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Michele Re Fiorentin
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
| | - Giancarlo Cicero
- Department of Applied Science and TechnologyPolitecnico di Torinocorso Duca degli Abruzzi 24Torino10129Italy
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8
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Moon G, Min SY, Han C, Lee SH, Ahn H, Seo SY, Ding F, Kim S, Jo MH. Atomically Thin Synapse Networks on Van Der Waals Photo-Memtransistors. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203481. [PMID: 35953281 DOI: 10.1002/adma.202203481] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/30/2022] [Indexed: 06/15/2023]
Abstract
A new type of atomically thin synaptic network on van der Waals (vdW) heterostructures is reported, where each ultrasmall cell (≈2 nm thick) built with trilayer WS2 semiconductor acts as a gate-tunable photoactive synapse, i.e., a photo-memtransistor. A train of UV pulses onto the WS2 memristor generates dopants in atomic-level precision by direct light-lattice interactions, which, along with the gate tunability, leads to the accurate modulation of the channel conductance for potentiation and depression of the synaptic cells. Such synaptic dynamics can be explained by a parallel atomistic resistor network model. In addition, it is shown that such a device scheme can generally be realized in other 2D vdW semiconductors, such as MoS2 , MoSe2 , MoTe2 , and WSe2 . Demonstration of these atomically thin photo-memtransistor arrays, where the synaptic weights can be tuned for the atomistic defect density, provides implications for a new type of artificial neural networks for parallel matrix computations with an ultrahigh integration density.
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Affiliation(s)
- Gunho Moon
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Seok Young Min
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Cheolhee Han
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Suk-Ho Lee
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Heonsu Ahn
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Seung-Young Seo
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Feng Ding
- Center for Multidimensional Carbon Materials, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
| | - Seyoung Kim
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
| | - Moon-Ho Jo
- Center for Van der Waals Quantum Solids, Institute for Basic Science (IBS), Pohang, 37673, Republic of Korea
- Department of Materials Science and Engineering, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Republic of Korea
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9
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He H, Zhao J, Huang P, Sheng R, Yu Q, He Y, Cheng N. Performance improvement in monolayered SnS 2 double-gate field-effect transistors via point defect engineering. Phys Chem Chem Phys 2022; 24:21094-21104. [PMID: 36018265 DOI: 10.1039/d2cp03427a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Owing to the relatively high carrier mobility and on/off current ratio, monolayered SnS2 has the advantage of suppressing drain-to-source tunneling for short channels, rendering it a promising candidate in field-effect transistor (FET) applications. To extend the scaling limit of the channel length, we propose to rationally modulate the electronic properties of monolayered SnS2 through the customized design of point defects and simulate its performance limit in sub-5 nm double-gate FETs (DGFETs), using density functional theory combined with nonequilibrium Green's function formalism. Among all types of point defects, the Se atom as a substitutional dopant (SeS) can nondegenerately inject electrons into each monolayered (ML) SnS2 2 × 4 × 1 supercell, whereas the Sn vacancy (VSn) defect exhibits an opposite doping effect. By adjusting the lateral Schottky barrier height between electrodes and the channel region, the on-state current (Ion), on/off ratio, delay time, and power-delay product in the formed n-type SeS-doped SnS2 and p-type VSn-doped SnS2 DGFETs with a channel length of 4.5 nm have been remarkably improved, fulfilling the requirements of the International Technology Roadmap for Semiconductors (ITRS) for high-performance applications in the 2028 horizon. Our work unveils the great significance of point defect engineering for applications in ultimately scaled electronics.
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Affiliation(s)
- Haibo He
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
| | - Jianwei Zhao
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
| | - Pengru Huang
- School of Material Science & Engineering, Guangxi Key Laboratory of Information Materials and Guangxi Collaborative Innovation Center of Structure and Property for New Energy and Materials, Guilin University of Electronic Technology, Guilin 541004, P. R. China
| | - Rongfei Sheng
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
| | - Qiaozhen Yu
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
| | - Yuanyuan He
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
| | - Na Cheng
- College of Material and Textile Engineering, Key Laboratory of Yarn Materials Forming and Composite Processing Technology, Jiaxing University, Jiaxing 314001, Zhejiang, P. R. China.
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10
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Lee K, Park J, Choi S, Lee Y, Lee S, Jung J, Lee JY, Ullah F, Tahir Z, Kim YS, Lee GH, Kim K. STEM Image Analysis Based on Deep Learning: Identification of Vacancy Defects and Polymorphs of MoS 2. NANO LETTERS 2022; 22:4677-4685. [PMID: 35674452 DOI: 10.1021/acs.nanolett.2c00550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Scanning transmission electron microscopy (STEM) is an indispensable tool for atomic-resolution structural analysis for a wide range of materials. The conventional analysis of STEM images is an extensive hands-on process, which limits efficient handling of high-throughput data. Here, we apply a fully convolutional network (FCN) for identification of important structural features of two-dimensional crystals. ResUNet, a type of FCN, is utilized in identifying sulfur vacancies and polymorph types of MoS2 from atomic resolution STEM images. Efficient models are achieved based on training with simulated images in the presence of different levels of noise, aberrations, and carbon contamination. The accuracy of the FCN models toward extensive experimental STEM images is comparable to that of careful hands-on analysis. Our work provides a guideline on best practices to train a deep learning model for STEM image analysis and demonstrates FCN's application for efficient processing of a large volume of STEM data.
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Affiliation(s)
- Kihyun Lee
- Department of Physics, Yonsei University, Seoul 03722, Korea
| | - Jinsub Park
- Department of Physics, Yonsei University, Seoul 03722, Korea
| | - Soyeon Choi
- Department of Physics, Yonsei University, Seoul 03722, Korea
| | - Yangjin Lee
- Department of Physics, Yonsei University, Seoul 03722, Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Korea
| | - Sol Lee
- Department of Physics, Yonsei University, Seoul 03722, Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Korea
| | - Joowon Jung
- Department of Physics, Yonsei University, Seoul 03722, Korea
| | - Jong-Young Lee
- Department of Material Science and Engineering, Seoul National University, Seoul 08826, Korea
| | - Farman Ullah
- Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, Korea
| | - Zeeshan Tahir
- Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, Korea
| | - Yong Soo Kim
- Department of Physics and Energy Harvest Storage Research Center, University of Ulsan, Ulsan 44610, Korea
| | - Gwan-Hyoung Lee
- Department of Material Science and Engineering, Seoul National University, Seoul 08826, Korea
- Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Korea
- Institute of Engineering Research, Seoul National University, Seoul 08826, Korea
- Institute of Applied Physics, Seoul National University, Seoul 08826, Korea
| | - Kwanpyo Kim
- Department of Physics, Yonsei University, Seoul 03722, Korea
- Center for Nanomedicine, Institute for Basic Science (IBS), Seoul 03722, Korea
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Yu H, Li D, Shang Y, Pei L, Zhang G, Yan H, Wang L. Transport properties of MoS 2/V 7(Bz) 8 and graphene/V 7(Bz) 8 vdW junctions tuned by bias and gate voltages. RSC Adv 2022; 12:17422-17433. [PMID: 35765433 PMCID: PMC9189623 DOI: 10.1039/d2ra02196j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 06/06/2022] [Indexed: 12/02/2022] Open
Abstract
The MoS2/V7(Bz)8 and graphene/V7(Bz)8 vdW junctions are designed and the transport properties of their four-terminal devices are comparatively investigated based on density functional theory (DFT) and the nonequilibrium Green's function (NEGF) technique. The MoS2 and graphene nanoribbons act as the source-to-drain channel and the spin-polarized one-dimensional (1D) benzene-V multidecker complex nanowire (V7(Bz)8) serves as the gate channel. Gate voltages applied on V7(Bz)8 exert different influences of electron transport on MoS2/V7(Bz)8 and graphene/V7(Bz)8. In MoS2/V7(Bz)8, the interplay of source and gate bias potentials could induce promising properties such as negative differential resistance (NDR) behavior, output/input current switching, and spin-polarized currents. In contrast, the gate bias plays an insignificant effect on the transport along graphene in graphene/V7(Bz)8. This dissimilarity is attributed to the fact that the conductivity follows the sequence of MoS2 < V7(Bz)8 < graphene. These transport characteristics are examined by analyzing the conductivity, the currents, the local density of states (LDOS), and the transmission spectra. These results are valuable in designing multi-terminal nanoelectronic devices.
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Affiliation(s)
- Hong Yu
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Danting Li
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Yan Shang
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Lei Pei
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Guiling Zhang
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Hong Yan
- School of Materials Science and Chemical Engineering, Harbin University of Science and Technology Harbin 150040 P. R. China
| | - Long Wang
- HeiLongJiang Construction Investment Group Co. Ltd No. 523, Sanda Dongli Road Harbin 150040 P. R. China
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