In this work are studied the composition of both oxidesobtained on to the natural surface of layered InSe single crystals and that of the Ga2O3 semiconductor, with own structural defects, obtained by thermal annealing of Ga2S3 single crystals in the normal atmosphere. The thermal range of oxides layersobtaining on the surface of both InSe and Ga2S3 is determined. The correlation between the oxide crystallites size and both the treatment duration and temperature is established.The optical transitions’ character, optical constants and the band gap of nano and microgranular Ga2O3 and In2O3 oxides are determined from diffuse reflectance measurements. The luminescence spectra of obtained structures are studied and the recombination levels diagram in the Ga2O3 and In2O3 nanocrystalline layers are determined.The diagram of electron trapping levels in the nanogranular oxide layers is determined from TSL curves analysis. Also, the influence of molecular gas adsorbed in the oxide layer on to luminescent recombination processes and the trapping of nonequilibrium charge carriers is studied.