Si掺杂Al_2O_3电子结构的第一性原理计算

本文采用第一性原理对纯Al2O3和Si掺杂的Si0.167Al0.833O1.5,Si0.25Al0.75O1.5晶体体系的能带结构、态密度进行了计算分析.结果发现:随着Si在Al2O3晶体中所占比例的增加,体系能隙变小,在Si0.25Al0.75O1.5晶体体系中能隙已降到2.5 e V,表明该体系为半导体材料;而在掺杂的体系中有数条分散的能带穿过了费米能级,即可以预测该掺杂体系有特别的光电性质;同时对比纯Al2O3和Si掺杂的Si0.167Al0.833O1.5,Si0.25Al0.75O1.5晶体体系的总态密度,发现掺杂体系的价带和导带向低能区域移动.

First principles calculation of electronic structures of Si-doped Al2O3

The first-principles methods are used to study the band structures and the densities of states of the pure Al2O3 and the Si0.167Al0.833O1.5, Si0.25Al0.75O1.5 of Si-doped Al2O3. It is shown that the energy gap decreases as the proportion of Si increases in Al2O3 crystal and it is reduced to 2.5eV in the crystal system of Si 0.25Al0.75O1.5. These indicate that the Si-doped Al2O3 is semiconductor material. However, in the Si-doped system, there are several band energies across the Fermi level, predicting that the doped system has special photoelectric properties. Comparing the total density of states of the pure Al2O3 with those of Si 0.167Al0.833O1.5 and Si0.25Al0.75O1.5 crystal systems, it is found that the valence band and the conduction band of the Si-doped Al2O3 move to the low-energy region.