Vacuum annealing temperature on spray In2S3 layers

Indium sulfide In2S3 thick films are deposited on glass substrates using spray technique over the optimum conditions experiments (T-s = 340 degrees C, S/In = 2). The films are polycrystalline and have thickness of about 1.8 mu m. These films are annealed in a vacuum sealed pyrex tubes (10(-5) torr). Physico-chemical characterizations by SEM observation, X-ray diffraction and EDX analysis are undertaked on these films. This treatment has improved crystallinity of samples. It has allowed thus to stabilize beta and gamma varieties of In2S3 material. In2O3 and In6S7 phases have appeared with very weak intensities at high temperatures. The best structure quality are obtained at 300 degrees C for the optimum annealed temperature (T-s = 340 degrees C, S/In = 2), for which samples are constituted in dominance by. phase oriented preferentially towards (102). The grain size is 42 nm of this phase. Chemical composition of such films has changed relatively to non-treated film but it seems not be affected by treatment temperature. Atomic molar ratio S/In is obtained for 0.9. Optical study shows that these layers are transparent in the visible and optical direct band gap increases as function of annealed temperature.