Thermal transformations in nanodimensional Pb—WO3 systems

Transformations in Pb-WO₃ nanodimensional systems are investigated in dependence on the thickness of the Pb and WO₃ films, temperature, and thermal treatment duration by means of optical spectroscopy, microscopy, and gravimetry. The contact potential difference for Pb and WO₃ films and the photoelectric power of Pb-WO₃ systems is measured. A diagram of the energy bands of Pb-WO₃ systems is constructed. A model of thermal transformation for the WO₃ films in Pb-WO₃ systems is suggested. The model involves the redistribution of equilibrium charge carriers on the contact, formation of the ((V_a)⁺⁺e]) center during the preparation of a WO₃ film, its transformation into a (e(V_a)⁺⁺e]) center during the formation of the Pb-WO₃ systems, and thermal ionization of the (e(V_a)⁺⁺e]) center.