Zhang Shuhui, Wang Xinxin, Wang Yuanyuan, Zhang Haona, Huang Baibiao, Dai Ying, Wei Wei
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China.
J Phys Chem Lett. 2022 Jun 2;13(21):4807-4814. doi: 10.1021/acs.jpclett.2c01195. Epub 2022 May 26.
Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) hold great promise in electronics and optoelectronics due to their novel electronic and optical properties. In TMDCs, structural defects are inevitable and might play a decisive role in device performance. In this work, point defects, line vacancies, and 60° grain boundaries (GBs) are explored in 2D Janus MoSSe, a new member to the family of TMDCs, by means of the first-principles calculations. S and Se vacancies are found to be the most favorable point defects, and they tend to aggregate along the zigzag direction to form line vacancies. Comparing with isolated point defects, line vacancies induced in-gap states are more dispersive. In particular, 60° GBs behave as one-dimensional metallic quantum wires, as a consequence of the polar discontinuity. Thus, effectively controlling the formation of defects at nanoscale brings new electronic characteristics, providing new opportunities to broaden the applications of 2D TMDCs.
二维（2D）过渡金属二硫属化物（TMDCs）因其新颖的电学和光学特性，在电子学和光电子学领域极具潜力。在TMDCs中，结构缺陷不可避免，且可能对器件性能起决定性作用。在本工作中，通过第一性原理计算，对二维Janus MoSSe（TMDCs家族的新成员）中的点缺陷、线空位和60°晶界（GBs）进行了研究。发现S和Se空位是最有利的点缺陷，它们倾向于沿锯齿方向聚集形成线空位。与孤立点缺陷相比，线空位诱导的带隙态更具色散性。特别地，由于极性不连续性，60°GBs表现为一维金属量子线。因此，在纳米尺度上有效控制缺陷的形成带来了新的电子特性，为拓宽二维TMDCs的应用提供了新机遇。
