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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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Mao GQ, Yan ZY, Xue KH, Ai Z, Yang S, Cui H, Yuan JH, Ren TL, Miao X. DFT-1/2 and shell DFT-1/2 methods: electronic structure calculation for semiconductors at LDA complexity. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:403001. [PMID: 35856860 DOI: 10.1088/1361-648x/ac829d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
It is known that the Kohn-Sham eigenvalues do not characterize experimental excitation energies directly, and the band gap of a semiconductor is typically underestimated by local density approximation (LDA) of density functional theory (DFT). An embarrassing situation is that one usually uses LDA+Ufor strongly correlated materials with rectified band gaps, but for non-strongly-correlated semiconductors one has to resort to expensive methods like hybrid functionals orGW. In spite of the state-of-the-art meta-generalized gradient approximation functionals like TB-mBJ and SCAN, methods with LDA-level complexity to rectify the semiconductor band gaps are in high demand. DFT-1/2 stands as a feasible approach and has been more widely used in recent years. In this work we give a detailed derivation of the Slater half occupation technique, and review the assumptions made by DFT-1/2 in semiconductor band structure calculations. In particular, the self-energy potential approach is verified through mathematical derivations. The aims, features and principles of shell DFT-1/2 for covalent semiconductors are also accounted for in great detail. Other developments of DFT-1/2 including conduction band correction, DFT+A-1/2, empirical formula for the self-energy potential cutoff radius, etc, are further reviewed. The relations of DFT-1/2 to hybrid functional, sX-LDA,GW, self-interaction correction, scissor's operator as well as DFT+Uare explained. Applications, issues and limitations of DFT-1/2 are comprehensively included in this review.
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Affiliation(s)
- Ge-Qi Mao
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
| | - Zhao-Yi Yan
- School of Integrated Circuits, Tsinghua University, Beijing 100084, People's Republic of China
| | - Kan-Hao Xue
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
| | - Zhengwei Ai
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
| | - Shengxin Yang
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
| | - Hanli Cui
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
| | - Jun-Hui Yuan
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
| | - Tian-Ling Ren
- School of Integrated Circuits, Tsinghua University, Beijing 100084, People's Republic of China
| | - Xiangshui Miao
- School of Integrated Circuits, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, 430074, People's Republic of China
- Hubei Yangtze Memory Laboratories, Wuhan 430205, People's Republic of China
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