The heavily intermixed In2S3/Cu(In, Ga)Se2 interface as Revealed by photoelectron and soft x-ray emission spectroscopy

We report on the characterization of the chemical and electronic interface structure of the heavily intermixed In
₂
S
₃
/Cu(In, Ga)Se
₂
(CIGSe) interface. Discussing our findings inferred from direct and inverse photoemission as well as soft x-ray emission spectroscopy, we particularly focus on the impact of the interfacial intermixing/interdiffusion processes on the electronic band alignment at the interface. Furthermore, we present deposition-temperature-dependent data on the (In, Al)
₂
S
₃
/CIGSe interface. We find that the chemical processes at the buffer/absorber interface are thermally activated with a threshold temperature of approximately 200°C.