搜索

x
中国物理学会期刊

基于形变势理论的掺杂计算Sb2Se3空穴迁移率

CSTR: 32037.14.aps.73.20231406

Carrier mobility in doped Sb2Se3 based on deformation potential theory

CSTR: 32037.14.aps.73.20231406
PDF
HTML
导出引用
  • 硒化锑(Sb2Se3)是一种元素丰富、经济且无毒的太阳电池吸收层材料. 太阳电池的性能在很大程度上取决于载流子的传输特性, 然而在Sb2Se3中, 这些特性尚未得到很好的理解. 通过密度泛函理论和形变势理论, 本文对纯Sb2Se3以及掺杂了As, Bi的Sb2Se3的空穴传输特性进行研究, 计算并分析了影响迁移率的3个关键参数: 有效质量、形变势和弹性常数. 结果显示, 有效质量对迁移率具有最大影响, 掺杂Bi的Sb2Se3表现出最高的平均迁移率. 同时发现, Sb2Se3的空穴迁移率呈现出明显的各向异性, 其中x方向的迁移率远高于y, z方向, 这应该与x方向的原子主要以较强的共价键连接, 而y, z方向以较弱的范德瓦耳斯力连接有关. 载流子传输能力强的方向有助于有效传输和收集光生载流子, 本研究从理论上强调了控制Sb2Se3沿特定方向生长的重要性.

     

    Antimony selenide (Sb2Se3) is an element-rich, cost-effective, and non-toxic material used as an absorber layer in solar cells. The performance of solar cells is significantly influenced by the transport characteristics of charge carriers. However, these characteristics in Sb2Se3 have not been well understood. In this work, through density functional theory and deformation potential theory, we investigate the hole transport properties of pure Sb2Se3 and As-, Bi-doped Sb2Se3. The incorporation of as element and Bi element does not introduce additional impurity levels within the band gap. However, the band gaps are reduced in both As-Sb2Se3 and Bi-Sb2Se3 due to the band shifts of energy levels. This phenomenon is primarily attributed to the interactions between the unoccupied 4p and 6p states of the doping atoms and the unoccupied 4p states of Se atoms, as well as the unoccupied 5p states of Sb atoms. In this study, we calculate and analyze three key parameters affecting mobility: effective mass, deformation potential, and elastic constants. The results indicate that effective mass has the greatest influence on mobility, with Bi-Sb2Se3 exhibiting the highest average mobility. The average effective mass is highest in As-Sb2Se3 and lowest in Bi-Sb2Se3. The elastic constants of the As- and Bi-doped Sb2Se3 structures show minimal differences compared with that of the intrinsic Sb2Se3 structure. By comparing the intrinsic, As-doped, and Bi-doped Sb2Se3, it is evident that doping has a minor influence on deformation potential energy along various directions. The study reveals that the hole mobility in Sb2Se3 displays significant anisotropy, with higher mobilities observed in the x-direction and the y-direction than in the z-direction. This discrepancy is attributed to stronger covalent bonding primarily in the x- and y-direction, while in the z-direction weaker van der Waals forces is dominant. The directions with enhanced charge carrier transport capability contribute to efficient transfer and collection of photo-generated charge carriers. Therefore, our research theoretically underscores the significance of controlling the growth of antimony selenide along specific directions.

     

    目录

    /

    返回文章
    返回