Material School of Shenzhen University, Shenzhen Key Laboratory of Advanced Functional Material, Shenzhen, 518060, Guangdong, People's Republic of China. Department of Electrical and Computer Engineering, George Mason University, Fairfax, VA 22030, United States of America.
Nanotechnology. 2017 Sep 8;28(36):365202. doi: 10.1088/1361-6528/aa7a34. Epub 2017 Jun 19.
In this paper, we report a comprehensive modeling and simulation study of constructing hybrid layered materials by alternately stacking MoS and WSe monolayers. Such hybrid MoS/WSe hetero-multilayers exhibited direct bandgap semiconductor characteristics with bandgap energy (E ) in a range of 0.45-0.55 eV at room temperature, very attractive for optoelectronics (wavelength range 2.5-2.75 μm) based on thicker two-dimensional (2D) materials. It was also found that the interlayer distance has a significant impact on the electronic properties of the hetero-multilayers, for example a five orders of magnitude change in the conductance was observed. Three material phases, direct bandgap semiconductor, indirect bandgap semiconductor, and metal were observed in MoS/WSe hetero-multilayers, as the interlayer distance decreased from its relaxed (i.e., equilibrium) value of about 6.73 Å down to 5.50 Å, representing a vertical pressure of about 0.8 GPa for the bilayer and 1.5 GPa for the trilayer. Such new hybrid layered materials are very interesting for future nanoelectronic pressure sensor and nanophotonic applications. This study describes a new approach to explore and engineer the construction and application of tunable 2D semiconductors.
在本文中，我们报告了通过交替堆叠 MoS 和 WSe 单层来构建混合层状材料的综合建模和模拟研究。这种混合的 MoS/WSe 异质多层结构表现出直接带隙半导体特性，其带隙能量 (E) 在室温下为 0.45-0.55 eV，非常适合基于较厚二维 (2D) 材料的光电子学（波长范围 2.5-2.75 μm）。还发现层间距离对异质多层的电子性质有显著影响，例如观察到电导有五个数量级的变化。在 MoS/WSe 异质多层中观察到三种材料相，即直接带隙半导体、间接带隙半导体和金属，随着层间距离从其弛豫（即平衡）值约 6.73 Å 减小到 5.50 Å，对于双层结构代表约 0.8 GPa 的垂直压力，对于三层结构代表约 1.5 GPa 的垂直压力。这种新型混合层状材料对于未来的纳米电子压力传感器和纳米光子学应用非常有趣。本研究描述了一种新的方法来探索和设计可调谐 2D 半导体的构建和应用。
