硅和锗纳米线的原子排布和电荷分布的密度泛函紧束缚方法研究

Investigation on atomic arrangement and Mülliken populations of Si and Ge nanowires by density functional tight binding simulations

低维硅锗材料是制备纳米电子器件的重要候选材料,是研发高效率、低能耗和超高速新一代纳米电子器件的基础材料之一,有着潜在的应用价值.采用密度泛函紧束缚方法分别对厚度相同、宽度在0.272 nm~0.554 nm之间的硅纳米线和宽度在0.283 nm~0.567 nm之间的锗纳米线的原子排布和电荷分布进行了计算研究.硅、锗纳米线宽度的改变使原子排布,纳米线的原子间键长和键角发生明显改变.纳米线表层结构的改变对各层内的电荷分布产生重要影响.纳米线中各原子的电荷转移量与该原子在表层内的位置相关.纳米线的尺寸和表层内原子排列结构对体系的稳定性产生重要影响.

Low dimensional silicon and germanium materials are important candidates for the preparation of nano-electronic devices,and are the basis materials to develop novel generations of nano-electronic devices with high efficiency,low energy consumption and ultra-high speed.The structures,stabilities,and charge distributions of the silicon nanowires with their widths in the range of 0.272 nm~0.554 nm and the germanium nanowires with their widths in the range of 0.283 nm~0.567 nm and with the same thickness are studied by Density Functional Tight Binding algorithm.The width changes of silicon and germanium nanowires have obvious influence on the atomic arrangements,bond length,and bond angle.The changes of the surface structures are important to the surface charge distribution.The studies also find that the atomic charge transfer values in the nanowires are closely related to the distance of the atoms moving from the surface.The widths of the nanowires and atomic arrangements in the surface regions are the main factors to affect their stability.