Si 掺杂 Al2O3电子结构的第一性原理计算

摘要

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 Al 2 O3 crystal and it is reduced to 2.5 eV in the crystal system of Si0.25 Al0.75 O1.5.These indicate that the Si-doped Al2 O3 is semiconductor material.However, in the Si-doped sys-tem, there are several band energies across the Fermi level , predicting that the doped system has special photoe-lectric properties.Comparing the total density of states of the pure Al 2 O3 with those of Si0.167 Al0.833 O1.5 and Si0.25 Al0.75 O1.5 crystal systems, it is found that the valence band and the conduction band of the Si-doped Al2 O3 move to the low-energy region.%本文采用第一性原理对纯Al2 O3和Si掺杂的Si0.167 Al0.833 O1.5， Si0.25 Al0.75 O1.5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 Al2 O3晶体中所占比例的增加，体系能隙变小，在Si0.25 Al0.75 O1.5晶体体系中能隙已降到2.5 eV，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 Al2 O3和 Si 掺杂的Si0.167 Al0.833 O1.5， Si0.25 Al0.75 O1.5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.