Conversion of chemically deposited intrinsic CdSe thin films to n-type coatings by a postdeposition process is described. A Cd:Se-In thin film consisting of a CdSe thin film similar to 0.15 mu m thick and a thermally evaporated indium film similar to 0.02 mu m thick was air annealed at 325 degrees C for 1 h. The resulting thin film coating of CdSe:In (0.15 mu m)-In2O3 (0.03 mu m) exhibits a sheet resistance of 790 Omega/square and an n-type conductivity of similar to 400 Omega(-1) cm for the In2O3 top layer. Etching of the film with 1 M HCl for 6 h removes the superficial In2O3 from the coating, and the underlying CdSe with indium doping shows a sheet resistance of 15 k Omega/square which corresponds to electrical. conductivity (n-type) of similar to 0.4 Omega(-1) cm(-1). The composition of the film and its variation along the depth are established through analyses of x-ray diffraction pattern and xray fluorescence spectra as well as the photocurrent response of the annealed films recorded before and after chemical etching.