扶手椅型缺陷硫化钼纳米带电子性质的第一性原理计算

基于密度泛函理论的第一性原理计算,研究了含空位缺陷的扶手椅型二硫化钼纳米带的电子性质.发现缺陷会导致纳米带结构稳定性降低,单空位钼缺陷和三空位缺陷使得纳米带从半导体变成金属性,而单空位硫缺陷和两种双空位缺陷仅减小纳米带的带隙;电子态密度和能带的本征态表明缺陷纳米带费米能级附近的杂质态主要是缺陷态的贡献.研究了四类半导体性质的纳米带带隙与宽度的关系,对于完整的纳米带,带隙随宽度以3为周期振荡变化;而引入空位缺陷后,纳米带的带隙振荡不再具有周期且振荡幅度变小.同时发现,当缺陷的浓度变小后,缺陷仅使纳米带的带隙减小,不会使其变为金属性.这些结果有望打开其在新型纳电子器件中的应用潜能.

First-Principles Calculations of Electronic Properties of Defective Armchair MoS2 Nanoribbons

We investigated the electronic properties of armchair MoS₂ nanoribbons with vacancy defects using a first-principles method based on density functional theory. It was found that defects reduced the stability of armchair MoS₂ nanoribbons. Mo vacancies and MoS₂ triple vacancies can both change the band structures of nanoribbons from semiconductor to metallic, whereas S vacancies, 2S divacancies, and MoS divacancies only decrease the bandgap. The densities of states and eigenstates of the nanoribbons indicated that impurity bands near the Fermi level basically contributed to the defect states. The relationships between the bandgap and width of four types of semiconducting nanoribbons were simulated. Nanoribbons with no defects have a bandgap that oscillates with width in a period of three, but the bandgap changes nonperiodically for nanoribbons with S vacancies, 2S divacancies, and MoS divacancies. We also found that when the concentration of defects decreased, the vacancy defects did not destroy the nanoribbon semiconducting behavior but only decreased the bandgap. These results open up possibilities for MoS₂ nanoribbon applications in novel nanoelectronic devices.