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采用第一性原理局域密度近似法计算了V2O5的电子态密度和能带结构以及Li嵌入后对其电子结构和光学性质的影响。计算结果表明,V2O5是间接带隙半导体,Li的嵌入并没有改变其电子的跃迁方式。但Li的嵌入使得V2O5导带能量下移,禁带宽度减小,导带中原有的劈裂被分裂的能级填满;同时致使价带出现展宽。电子态密度计算结果表明Li的嵌入对临近的O和V的电子结构有较大的影响。Li2s电子的注入提高了V2O5的费米能级并导致其进入导带。由于价带中的电子只能跃迁到费米能级以上的导带空能级,这致使体系实际的光学带隙增大。同时随着Li注入量的进一步增加,价带的展宽更为明显,费米能级亦呈升高的趋势,使得光学带隙随着Li注入量的增加而增大。
The first-principles local density approximation method was used to calculate the electronic density of states and band structure of V2O5 and the influence of Li on its electronic structure and optical properties. The calculated results show that V2O5 is an indirect band gap semiconductor. The insertion of Li does not change the transition mode of electrons. However, the insertion of Li makes the energy of the conduction band of V2O5 go down, the forbidden band width decreases, and the original splitting in the conduction band is filled up by the splitting energy level; at the same time, the valence band broadens. The calculation of electronic density of states shows that the embedding of Li has a great influence on the electronic structure of O and V nearby. The injection of Li2s electrons increases the Fermi level of V2O5 and causes it to enter the conduction band. Since the electrons in the valence band can only jump to the conduction band vacancy level above the Fermi level, the actual optical band gap of the system increases. At the same time, with the further increase of Li implantation, the valence band broadening is more obvious, and the Fermi level also shows an upward trend, which makes the optical bandgap increase with the increase of Li implantation.