Influence of the copper deficiency and anionic composition on band-energy diagram of bulk kesterite CZTSSe

The influence of the chemical composition on band edges and Fermi level of the Cu2ZnSn(SxSe1-x)4 stoichiometric compounds was investigated. The Cu-poor compounds, Cu1.70Zn1.15SnSSe3 and Cu1.70Zn1.15SnS2Se2, were also studied according to the same approach. As already reported, the absorption threshold increases linearly from 1.05 to 1.48 eV with increasing sulfur content. Simultaneously, the conduction band moves from −4.4 to −3.8 eV...