In the work the results of studies of thin-film samples of nanoclusters of tantalum and molybdenum metals on the surface of silicon dioxide SiO2/Si (001) at room temperature are presented. The chemical composition and electronic structure of the obtained nanocluster films of Ta and Mo were controlled in situ by X-ray photoelectron spectroscopy (XPS). Susceptibility to oxidation during the exposure to the atmosphere of then nanocluster films, as well as their thermal stability when heated in a vacuum to 600 °C were studied ex situ by the XPS method. The size and shape of the nanoclusters composing the film were estimated ex situ by analyzing images obtained with a scanning electron microscope. The band structure before and after oxidation was studied by measuring the bandgap of the formed Ta and Mo films by the method of electron energy loss characteristic spectroscopy (REELS). Conclusions about thermoelectric properties of the formed nanocluster films of Ta and Mo were made.