Preparation of homogeneous Cu(InGa)Se2 films by selenization of metal precursors in H2Se atmosphere

Abstract

Homogeneous single phase Cu(InGa)Se₂ films with Ga/(In+Ga)=0.25–0.75 were formed by reacting Cu–Ga–In precursor films in H₂Se followed by an anneal in Ar. X‐ray diffraction and Auger analysis show that the metal precursors reacted only in H₂Se were multiphase films having a layered CuInSe₂/CuGaSe₂ structure. Solar cells made with the multiphase films have properties similar to CuInSe₂ devices. Cells made with the annealed single phase films behave like Cu(InGa)Se₂ devices with the band gap expected for the precursor composition.