Electrodeposition of zinc telluride

Abstract

The synthesis of polycry stalline thin films of cubic ZnTe by electrochemical plating on conducting substrates (titanium, nickel and F:SnO 2 glass) is described. Electrodeposition involves potentiostatic reduction from an acid aqueous bath. The influence of bath composition (concentrations of the precursors TeO 2 and Zn 2+, and pH), deposition potential and temperature on the chemical composition of the films and on their crystallinity is discussed. The thin films were characterized by X-ray diffraction (XRD), electron probe microanalysis, scanning electron microscopy, and optical measurements. For optimized deposition parameters, the XRD pattern of a single-phase, cubic ZnTe was found. Otherwise, the patterns of either Zn or Te were found in addition in some samples. Best results (stoichiometric ZnTe films with a reddish aspect) were obtained from TeO 2 saturated solution at a pH of 4.5,98 °C, and a Zn 2+ concentration of 0.02 M, employing deposition potentials between −0.8 V and −0.9 V vs. Ag AgCl . The optical and crystalline properties of the films improved by annealing for 1 h at 450 °C in argon. By this treatment excess Te found in samples prepared under certain conditions could also be removed.