Thin film CdS/CdTe solar cells

Abstract

The effects of processes used in making thin film ITO/CdS/CdTe/Au heterojunction solar cells have been investigated. In particular, air annealing the ITO/CdS/CdTe layer is shown, from spectral evidence, to produce a heterojunction. XPS evidence shows that this heating forms CdO and TeO₂ on the CdTe surface and that these are removed by a KOH etch. A further bromine/methanol etch leaves a Te-rich surface which forms an injecting contact with the Au top electrode into which the Te mixes.