Gadolinium Doping and Oxygen Vacancies in Vanadium Dioxide Thin Films: Effects on Microstructure and Properties

Abstract

Vanadium dioxide (VO2) has attracted considerable attention owing to the significant changes in its optical and electrical properties during metal-to-insulator phase transitions induced by thermal or laser irradiation. Such property makes VO2 a promising material for application in numerous fields, particularly in laser protection. This study examined the effects of gadolinium (Gd) doping on the microstructure and phase-transition characteristics of VO2 thin films. X-ray photoelectron spectroscopy, photoluminescence spectroscopy, X-ray diffraction, and ET-Raman spectroscopy were used to characterize the microstructure and content of VO2 thin films. In-situ Raman spectroscopy and Fourier-transform infrared spectroscopy were used to explore the transition process. The results showed that Gd doping introduces oxygen vacancies and alters the microstructure, with Gd3+ ions incorporated into the thin films. Increasing Gd sputtering power leads to a gradual increase in doping content and significant changes in phase-transition temperature and resistivity. These findings revealed the role of oxygen vacancies in regulating the microstructure and phase-transition characteristics of VO2 thin films, providing reference values for the structure and property regulation of other materials with metal–insulator transition characteristics.