Band alignment at the BaCuSeF/ZnTe interface

In situ photoemission spectroscopy experiments are used to characterize the interface between ZnTe and the wide band gap p-type semiconductor BaCuSeF. The contact is characterized by a null valence-band offset, a large conduction-band offset, and a chemically graded interface. By applying the transitivity rule for band offset and on the basis of similarities in chemical composition, BaCuSeF contact to chalcogenide photovoltaic absorber materials would be expected to have similar properties. By extension, BaCuChF (Ch=S,Se,Te) materials are suitable as p-layers in p-i-n double-heterojunction solar cells fabricated with CdTe, Cu(InGa)Se2, and Cu2ZnSnS4 absorbers.