Study on the preparation of structured CuInS2 films by ion exchange processes

We examined the preparation of microstructured CuInS2 thin films in a sequential morphology-transfer process. This low-cost process is suitable for micro- and nano-structuring of large areas. It starts from ZnO, which was electrodeposited as a film of vertically oriented columns. This was converted to ZnS by an anion exchange reaction in the gas phase with good reproduction of the outer morphology. Further conversion to nano-structured Cu2S, Ag2S, Bi2S3 and Sb2S3 by cation exchange in solution has already been proven, but more difficulties arose for the conversion to In2S3. This is attributed to the more oxophilic character of the In3+ ion, and to its destabilizing effect on organic reaction media at elevated temperature. A coarser-structured sample of In2S3 was obtained, on which the final conversion step to CuInS2 proceeded readily with retention of this morphology. (C) 2003 Elsevier Science B.V. All rights reserved.