DFT-MBJ方法研究S掺杂R3c-ZnTiO3的电子结构和光吸收性质

DFT-MBJ study on the electronic structure and optical absorption properties of S-doped R3c-ZnTiO3

采用基于密度泛函理论(DFT)和Modified Becke-Johnson(MBJ)势方法计算了R3c-ZnTiO3的电子结构和光吸收性质。计算结果表明本征R3c-ZnTiO3吸收很少的可见光,S掺杂R3c-ZnTiO3形成明显的S缺陷能级可以降低体系的带隙,促进可见光的吸收。随着S掺杂浓度增大的时候,对可见光吸收增强的效果更加的明显。计算的价带顶(VBM)和导带底(CBM)电荷分析表明S掺杂R3c-ZnTiO3时S原子占据主要的VBM电荷,同时容易发生VBM的S原子电荷向CBM的Ti原子电荷跃迁,拓展了R3c-ZnTiO3在光伏半导体方面的应用。

The electronic structure and optical absorption properties of R3c-ZnTiO3 were calculated based on density functional theory(DFT)and Modified Becke-Johnson(MBJ)potential method.The calculated results show that the intrinsic R3c-ZnTiO3 absorbed little visible light,and the S-doped R3c-ZnTiO3 formed a distinct S-defect energy level,which could reduce the band gap to promote the absorption of visible light.As the S doping concentration increased,the effect of enhanced absorption of visible light became more intensive.The calculated valence band maximum(VBM)and the conduction band minimum(CBM)charge analysis show that the S atom occupied the main VBM charge when S was doped with R3c-ZnTiO3.The transition between the VBM charge of S atom and the CBM charge of Ti atom could be relatively easy to emerge,which could expand application of R3c-ZnTiO3 as photovoltaic semiconductors.