Lim Bryan, Cui Xiang Yuan, Ringer Simon P
The University of Sydney, School of Aeronautical, Mechanical and Mechatronic Engineering and Australian Centre for Microscopy and Microanalysis, Sydney, New South Wales 2006, Australia.
Phys Chem Chem Phys. 2021 Mar 11;23(9):5407-5414. doi: 10.1039/d1cp00457c.
Accurate simulation of semiconductor nanowires (NWs) under strain is challenging, especially for bent NWs. Here, we propose a simple yet efficient unit-cell model to simulate strain-mediated bandgap modulation in both straight and bent NWs. This is with consideration that uniaxlly bent NWs experience continuous compressive and tensile strains through their cross-sections. A systematic investigation of a series of III-V and II-VI semiconductors NWs in both wurtzite and zinc blende polytypes is performed using hybrid density functional theory methods. The results reveal three common trend in bandgap evolution upon application of strain. Existing experimental measurements corroborate with our predictions concerning bandgap evolution as well as direct-indirect bandgap transitions upon strain. By examining the variation of previous theoretical studies, our result further highlights the significance of geometrical relaxtion in NW simulation. This simplified model is expected to be applicable to investigations of the electronic, optoelectronic, and sensorial properties of all semiconductor NWs.
精确模拟应变作用下的半导体纳米线（NWs）具有挑战性，尤其是对于弯曲的纳米线。在此，我们提出一种简单而有效的单胞模型，以模拟直纳米线和弯曲纳米线中应变介导的带隙调制。这是考虑到单轴弯曲的纳米线在其横截面上会经历连续的压缩应变和拉伸应变。使用混合密度泛函理论方法对纤锌矿和闪锌矿多型结构中的一系列III-V族和II-VI族半导体纳米线进行了系统研究。结果揭示了施加应变时带隙演化的三个共同趋势。现有的实验测量结果证实了我们关于带隙演化以及应变作用下直接-间接带隙跃迁的预测。通过研究先前理论研究的变化，我们的结果进一步突出了几何弛豫在纳米线模拟中的重要性。预计这个简化模型将适用于所有半导体纳米线的电子、光电和传感特性研究。
