STUDY AND DEVELOPMENT OF A GENERIC ELECTROCHEMICAL ION-EXCHANGE PROCESS TO FORM MXS OPTOELECTRONIC MATERIALS FROM ZNS PRECURSOR FILMS FORMED BY CHEMICAL-PRECIPITATION SOLUTION DEPOSITION

We have investigated the formation of a wide variety of metal sulfide films such as SnS and CdS by an electrochemical ion-exchange process where the metal cation of the desired product film exchanges with the Zn(II) in a ZnS film deposited on non-conductive substrates by chemical-precipitation solution techniques. The process works for most metals that can be electroplated from aqueous baths (i.e. more electrochemically noble than Zn) and yields nearly-stoichiometric, polycrystalline, and often photoconductive M(x)S films. Key advantages of the process include the very low hazard/toxicity and cost of the chemicals used in the process and the avoidance of secondary sulfide (PbS, CdS, In2S3, Sb2S3, etc.) sludges, colloids, precipitates, etc., of toxic and/or expensive metals. In particular, its outstanding photosensitivity and low toxicity point toward the utility of SnS formed by our method for photodetector applications.