Zheng K, Yang Q, Tan C J, Ye H Y, Chen X P
Key Laboratory of Optoelectronic Technology & Systems, Education Ministry of China, Chongqing University and College of Optoelectronic Engineering, Chongqing University, Chongqing 400044, China.
Phys Chem Chem Phys. 2017 Jul 19;19(28):18330-18337. doi: 10.1039/c7cp03388e.
Two new 2D materials, germanene and monolayer cadmium sulfide (CdS), have been theoretically predicted and experimentally fabricated recently. In this work, we conduct a systematic investigation of the geometry structure, electronic, optical, and transport properties of a CdS/germanene heterojunction by using density functional theory (DFT) combined with the nonequilibrium Green's function (NEGF) formalism. Despite the gapless nature of germanene, the CdS/germanene heterojunction is found to be a direct band gap semiconductor, with a band gap of 0.644 eV. In particular, applying external strain can effectively tune the electronic band structure and optical properties of the CdS/germanene bilayer in a wide range, and a semiconductor-metal transition can even be achieved. In addition, the transport property calculations show that the current-voltage (I-V) relation of the CdS/germanene bilayer exhibits sensitive responses to the applied strain with a marked change in the I-V relation. Such superior electronic, optical, and transport properties make the CdS/germanene heterobilayer a promising candidate for electronic and optical device applications.
最近，理论预测并通过实验制备出了两种新型二维材料——锗烯和单层硫化镉（CdS）。在这项工作中，我们采用密度泛函理论（DFT）结合非平衡格林函数（NEGF）形式体系，对CdS/锗烯异质结的几何结构、电子、光学和输运性质进行了系统研究。尽管锗烯具有无带隙特性，但CdS/锗烯异质结被发现是一种直接带隙半导体，带隙为0.644电子伏特。特别地，施加外部应变可以在很宽的范围内有效调节CdS/锗烯双层的电子能带结构和光学性质，甚至可以实现半导体-金属转变。此外，输运性质计算表明，CdS/锗烯双层的电流-电压（I-V）关系对外加应变表现出敏感响应，I-V关系有显著变化。这些优异的电子、光学和输运性质使得CdS/锗烯异质双层成为电子和光电器件应用的有前途的候选材料。
