Institute of Optoelectronics & Nanomaterials, Jiangsu Key Laboratory of Advanced Micro & Nano Materials and Technology, College of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094, People's Republic of China.
Nanotechnology. 2016 Jul 8;27(27):274001. doi: 10.1088/0957-4484/27/27/274001. Epub 2016 May 27.
Experimentally, GeS nanosheets have been successfully synthesized using vapor deposition processes and the one-pot strategy. Quite recently, GeS monolayer, the isoelectronic counterpart of phosphorene, has attracted much attention due to promising properties. By means of comprehensive first-principles calculations, we studied the stability and electronic properties of GeS monolayer. Especially, electric field and in-plane strain were used to tailor its electronic band gap. Upon applying electric field, the band gap of GeS monolayer greatly reduces and a semiconductor-metal transition happens under the application of a certain external electric field. Our calculations reveal that the band gaps of GeS monolayer are rather sensitive to the external electric field. On the other hand, for GeS under external strain, quite interestingly, we found that the band gap presents an approximately linear increase not only under compression strain but also under tensile strain from -10% to 10%. For biaxial compressive and tensile strains, the band gap follows the same trend as that of the uniaxial in the zigzag x direction. The present results provide a simple and effective route to tune the electronic properties of GeS monolayer over a wide range and also facilitate the design of GeS-based two-dimensional devices.
实验上，已经成功地使用气相沉积工艺和一锅法合成了 GeS 纳米片。最近，磷烯的等电子体 GeS 单层由于其具有良好的性质而受到了广泛关注。通过全面的第一性原理计算，我们研究了 GeS 单层的稳定性和电子性质。特别地，通过电场和平面内应变来调整其能带隙。施加电场后，GeS 单层的能带隙大大减小，在施加一定外电场的情况下会发生半导体-金属转变。我们的计算表明，GeS 单层的能带隙对外部电场非常敏感。另一方面，对于外部应变下的 GeS，有趣的是，我们发现不仅在压缩应变下，而且在从-10%到 10%的拉伸应变下，带隙呈现出近似线性的增加。对于双轴压缩和拉伸应变，带隙在锯齿 x 方向的单轴应变下呈现出相同的趋势。这些结果提供了一种简单而有效的方法来在很宽的范围内调节 GeS 单层的电子性质，并促进基于 GeS 的二维器件的设计。
