ELECTROCHEMICAL DEPOSITION OF ZNFES THIN-FILM SEMICONDUCTORS ON TIN OXIDE SUBSTRATES

The electrodeposition of ZnFeS thin film semiconductors on tin oxide s ubstrates in diethyleneglycol solution containing S-8, FeCl2 . 4H(2)O and ZnCl2 reagents was investigated. The potential region, where forma tion of the ZnFeS semiconductor occurs, was singled out between -0.6 a nd -1.0 V(SCE). Amorphous films were obtained after the deposition. Co nversion from amorphous to a crystalline structure was achieved by ann ealing the semiconductors at 285 degrees C in Argon. Chemical and morp hology characteristics were investigated by EDAX and SEM analyses. A d irect relationship was observed between the Fe and Zn concentration in the electrodeposition bath and the Zn/Fe ratio in the deposits. Thin film XRD analysis showed the crystallographic structures of sphalerite and pyrrhotite. The optical properties of the thin film semiconductor s changed as function of the Zn and Fe contents in the solution and in the films. The indirect energy gap transition varied from 0.37 to 3.1 eV, as the Zn/Fe ratio in the solution was increased. The suitable op tical properties of the thin films and the low-cost preparation proced ure appear as promising characteristics for the application of the ZnF eS system in solar energy conversion devices.