The influence of microstructure and phase composition of glass ceramics in the VO2–V2O5–P2O5–Cu2O–SnO2 system on the electrical properties related to the metal–semiconductor phase transition

Abstract

Abstract Phase composition, microstructure and electrical conductivity of glass ceramics in the VO2–V2O5–P2O5–SnO2 and VO2–V2O5–P2O5–Cu2O–SnO2 systems have been studied. Only crystalline phases VO2, SnO2 and vanadium phosphate glass of the V2O5–P2O5 system have been found in glass ceramic compositions in the VO2–V2O5–P2O5–SnO2 system. Besides the above-mentioned phases, probably the X-ray lines of V3O5, V4O7, V5O9, V6O11, V7O13, V4O9, V6O13, V2O5, SnO2, SnO, Sn2O3, Sn3O4 and CuO phases are observed in the X-ray spectra of glass ceramics in the VO2–V2O5–P2O5–Cu2O–SnO2 system. According to SEM/EDS data, these phases were observed as submicrometer fine-crystalline inclusions in glass on the surface of VO2 crystallites and between them. The formation of these phases was caused by the redox processes in the liquid phase during glass ceramics synthesis. The important role of tin oxides possessing high electrical conductivity and vanadium oxides exhibiting a low temperature of metal–semiconductor phase transition in the stabilization of glass ceramics electrical properties related to the phase transition in VO2 has been established.