Abstract The direction of Se-Mo-Se sheets to the Mo film is crucial for the thickness of Mo(S,Se)2 and the electrical conductivity, so as the back contact of Cu2ZnSn(S,Se)4 solar cells. In this study, the preferred orientation of Mo(S,Se)2 film changes from (100) peak to (103) peak, i.e. from perpendicular to the substrate to tilted to the substrate for Se-Mo-Se sheets as the roughness decrease of Mo back contact layer. The Se vapor can easily diffuse through the channels between Se-Mo-Se sheets when the formed Mo(S,Se)2 layer is (100) peak preferred with Se-Mo-Se sheets perpendicular to the substrate, and thus excessively thick Mo(S,Se)2 will be formed. Whereas, the Se-Mo-Se sheets are tilted to substrate when the preferred orientation of Mo(S,Se)2 is (103) peak. The tilted Se-Mo-Se sheets can act as a natural Se diffusion barrier to suppress the Se vapor diffusion through the already formed Mo(S,Se)2 layer to further selenize the remaining Mo film, and also can provide a good electrical conductivity. As a result, the thickness of Mo(S,Se)2 sharply decreased from 1500 nm to 200 nm with the surface morphology change of Mo back contact, which resulting in the decrease of series resistance of Cu2ZnSn(S,Se)4 solar cells from 2.94 Ω cm2 to 0.49 Ω cm2, and the increase of conversion efficiency of Cu2ZnSn(S,Se)4 solar cells from 6.98% to 9.04%.

中文翻译：

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为高效Cu 2 ZnSn(S,Se) 4 太阳能电池定制Mo(S,Se) 2 结构

摘要 Se-Mo-Se片对Mo薄膜的方向对Mo(S,Se)2的厚度和电导率至关重要，因此作为Cu2ZnSn(S,Se)4太阳能电池的背接触。在这项研究中，Mo(S,Se)2 薄膜的择优取向从 (100) 峰变为 (103) 峰，即随着粗糙度的降低，Se-Mo-Se 片材从垂直于基板变为倾斜于基板Mo背接触层。当形成的 Mo(S,Se)2 层为 (100) 峰时，Se 蒸气很容易通过 Se-Mo-Se 片之间的通道扩散，Se-Mo-Se 片垂直于基板，因此过厚的 Mo (S,Se)2 将形成。而当 Mo(S,Se)2 的优选取向为 (103) 峰时，Se-Mo-Se 片材向基板倾斜。倾斜的Se-Mo-Se片可以作为天然的Se扩散屏障，抑制Se蒸气通过已经形成的Mo(S,Se)2层扩散，进一步硒化剩余的Mo膜，还可以提供良好的导电性. 结果，随着Mo背接触表面形貌的变化，Mo(S,Se)2的厚度从1500 nm急剧下降到200 nm，导致Cu2ZnSn(S,Se)4太阳能电池的串联电阻降低从 2.94 Ω cm2 到 0.49 Ω cm2，Cu2ZnSn(S,Se)4 太阳能电池的转换效率从 6.98% 提高到 9.04%。