Kinetic tendencies of thermal transformations in nanosized Ni–MoO3 systems

Abstract

The transformations in nanosized Ni–MoO₃ systems were studied by optical spectroscopy, microscopy, and gravimetry depending on the thickness of the Ni (d = 1–40 nm) and MoO₃ (d = 3–50 nm) films, temperature (473–773 K), and thermal treatment time. The contact potential difference was measured for Ni and MoO3 films; photovoltage, for Ni–MoO₃ systems. An energy band diagram of the Ni–MoO₃ systems was constructed. A model of the thermal transformation of MoO₃ films in Ni–MoO₃ systems was suggested, which involves a redistribution of equilibrium charge carriers at the contact, formation of a [(V_а)⁺⁺е] center during the preparation of the MoO₃ film, the transformation of this center into an [е(V_а)⁺⁺е] center during the formation of Ni–MoO₃ systems, and the thermal transition of an electron to the level of the [(V_а)⁺⁺е] center to form an [е(V_а)⁺⁺е] center.