Physico-Chemical Characterization of Sprayed ?-Ag2S Thin Films

Silver sulfide Ag2S thin films have been prepared on pyrex and on SnO2/pyrex substrates by the spray pyrolysis technique (Dlala et al., Europ. Phys. J. A 2, 13 (1998)) using silver acetate and thiourea as precursors. The depositions were carried out at 200 and 250 °C. The X-ray diffraction spectra show that a substrate temperature Ts = 250 °C with a concentration ratio x = [S]/[Ag] = 2 in the solution allows to obtain well crystallized thin films with a preferential orientation along (-103) direction. Microprobe analysis as well as X-ray photoelectron spectroscopy (XPS) show that a nearly stoichiometric composition is obtained under these conditions. Moreover, we noticed by the same technique the presence of oxygen and carbon components particularly on the surface, due to a contamination effect. Indeed, it can be seen after etching that the intensity peaks decrease strongly, which indicated the weak proportion of these elements in the bulk of the films.