417 J. Electroanal. Chem., 310 (1991) 417-422 Elsevier !kquoia S.A., Lausanne JEC 01554 Short communication Anodic growth of CdS thin films: an in situ Raman spectroelectrochemical study D. Ham, Y. Son, K.K. Mishra and K. Rajeshwar * Department of Chemistry, Box 19065, The University of Texas at Arlington, Arlington, TX 760~9-0065 (USA) (Rweivcd 28 January 1991; in revised form 11 March 1991) INTRODUCTION There has been much recent interest in the fabrication of Group II-VI com- pound semiconductor thin films by anodic and cathodic electrodeposition methods [l-9]. These studies have been, in part, motivate by the use of these materials in solar and other optoelectronic device applications. A major problem with elec- trodeposition, however, is contamination of the target material with “impurity” phases; this is a particular difficulty with compound semiconductors (e.g., Te is usually deposited along with CeTe, cf. ref. 10). Unfortunately, monitoring of electrochemical parameters (e.g. charge, current, potential) alone, during the deposi- tion process, provides only limited info~ation content in terms of molecular details. It is advantageous to combine an in situ spectroscopic probe with electro- chemistry in such cases because of the extreme sensitivity and molecular selectivity of the former. We had used this strategy previously via cyclic photovolt~met~ to study electrodeposition mechanisms within the Group II-VI system 171. We now wish to report how Raman spectroscopy could be an especially useful probe for monitoring the chemistry associated with a semiconductor electrodeposition se- quence. We have observed routinely via surface analysis, high oxygen levels (up to - 13 atom %) in Group II-VI se~#nductor tbin films synthesized by the anodic route (cf. ref. 6). Analysis of Auger peak shapes and XRS binding energies, however, revealed the 0 to be not associated with the chalcogen component within the film. Further, depth profiles revealed this 0 to be uniformly distributed throughout the thin film, thus ruling out surface oxides as the origin. The present Raman spectro- * To whom correspondence should be addressed. 0022-0728/91/$O3.50 0 1991 - Elsevier Sequoia S.A.