Ga 高掺杂对 ZnO 的最小光学带隙和吸收带边影响的第一性原理研究*
First-principle study on the effect of high Ga doping on the optical band gap and the band-edge of optical absorption of ZnO*
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摘要: 采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法,建立了纯的和四种不同 Ga 掺杂量的 ZnO 超胞模型,分别对模型进行了几何结构优化、能带结构分布、态密度分布和吸收光谱的计算.结果表明,在本文限定的Ga 掺杂量2.08 at%-6.25 at%的范围内,随着 Ga 掺杂量的增加,掺杂后的 ZnO 体系体积变化不是很大,但是,掺杂体系 ZnO 的能量增加,掺杂体系变得越来越不稳定,同时,掺杂体系 ZnO 的 Burstein-Moss 效应越显著,最小光学带隙变得越宽,吸收带边越向高能方向移动.计算结果和实验结果相一致.
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关键词:
- Ga 高掺杂 ZnO /
- 电子结构 /
- 吸收光谱 /
- 第一性原理
Abstract: Based on the density functional theory (DFT), and using the first-principles plane-wave ultrasoft pseudopotential method, we set up models for a pure ZnO and four different concentrations of Ga-doped ZnO, and the geomertry optimization for the four modes was carried out. The total density of states (TDOS), the band structures (BS) and absorption spectrum were also calculated. Results show that the range of Ga doping amount is limited to 2.08 at% to 6.25 at% in this paper; when the doping concentration of Ga increases, the volume change of the system is not obvious; however, when is energy increases, the system will be unstable, the Burstein-Moss effect of its optical band gap will increase, and the absorption spectrum will shift to high energy. The results of calculation agree with the experimental data. -
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