Electrochemical deposition of ZnSe and (Zn,Cd)Se films from nonaqueous solutions

Films of (Zn,Cd)Se and ZnSe were electrodeposited from dimethylsulfoxide so lutions of elemental Se and the perchlorates of Zn and Gel. The composition of the mixed selenides could be controlled by variation of the deposition current density, utilizing diffusion control of the low concentrations of C d(ClO4)(2). The film composition was measured by X-ray photoelectron spectr oscopy and compared with the measured bandgap values extracted from optical transmission spectra. Photoelectrochemical photocurrent spectroscopy and c ontact potential difference (Kelvin probe) measurements both showed changes in apparent conductivity type with Zn concentration in the electrolyte fro m "n-type" (low Zn) concentration to "p-type" thigh Zn). This phenomenon is discussed in terms of preferential surface trapping of either electrons or holes at the nanocrystallite surface. (C) 2000 The Electrochemical Society . S0013-4651(99)08-109-4. All rights reserved.