扶手椅型二硫化钼纳米带的电子结构与边缘修饰

采用基于密度泛函理论的第一性原理计算方法, 研究了扶手椅型二硫化钼纳米带的几何构型与电子结构, 发现其稳定性与电子性质敏感地依赖于边缘修饰. 随着边缘修饰的H原子数增加, 纳米带变得更加稳定, 并在间接带隙半导体、半金属和直接带隙半导体之间转变. 纳米带的能带结构和电子态密度显示, 其费米能级附近的能带主要由边缘态贡献. 当二硫化钼纳米带两边用不同数目的H原子修饰时, 纳米带同时具有由这两种修饰引起的边缘态并且两种边缘态的相互影响很小. 研究了三类纳米带带隙与宽度的关系, 对于每个原胞修饰0个或8个H原子的纳米带, 带隙随宽度以3为周期振荡变化; 而对于每个原胞修饰4个H原子的纳米带, 带隙振荡不再具有周期并且振荡幅度变小.

Electronic Structure and Edge Modification of Armchair MoS2 Nanoribbons

The geometries and electronic properties of armchair MoS₂ nanoribbons were investigated by the first-principles method based on density functional theory. It was found that the stability and electronic properties of armchair MoS₂ nanoribbons sensitively depend on edge modification. Increasing the number of hydrogen atoms on the edge caused the nanoribbons to become more stable and transition between indirect-gap semiconductor, semi-metal and direct-gap semiconductor. The band structure and densities of states of the nanoribbons indicated that low energy bands contributed to edge states. Different hydrogen adsorption patterns on each edge induce two kinds of edge state on the nanoribbons and these two kinds of edge state have little effect on each other. The relationships between the bandgap and width of three types of nanoribbons were studied. Nanoribbons terminated with zero or eight hydrogen atoms in each unit cell have a bandgap that oscillates with width in a period of three, while the bandgap changes nonperiodically in those terminated with four hydrogen atoms.