Inspecting the band structure of ZnAs2, a promising optoelectronic material

In recent years, we are witnessing a resurgence of interest in the optoelectronic properties of semiconductors with bandgap in the near infrared and visible energy range. Binary II-V semiconductors are optically active, with anisotropic optical and electronic responses ideal for optoelectronic applications. Aim of this proposal is to perform, for the first time, a detailed investigation of the band structure of a member of this family, ZnAs2. Based on our preliminary time-and-angle-resolved photoemission study, the transiently populated conduction band displays a peculiar splitting that is not reproduced by ab initio calculations. In order to shed light on its origin, we plan to evaporate alkali metals to access the conduction band. By comparing static electronic doping and transient optical doping we expect to clarify the possible formation of excitons and their role in the optoelectronic properties of ZnAs2.