Nb-doped VO2 thin films with enhanced thermal sensing performance for uncooled infrared detection

Abstract

VO2 thin films are widely studied materials for uncooled infrared detection because of their high temperature coefficient of resistance. In this research, Nb-doped VO2 films were synthesized with the expectation that Nb doping would reduce the metal-insulator-transition temperature via electron doping and strain effects caused by the relatively large ionic radius of Nb, thus improving the resistance temperature coefficient of the doped films. The doped films displayed superior thermal sensing abilities compared with pure VO2 films. As the amount of Nb doping increased, the thermal hysteresis and resistivity of the doped films decreased, while the transition temperature range widened. When the Nb-doping content reached 10%, the temperature coefficient of resistance reached -3.2%/K, while the metal-insulator transition temperature dropped to 52.2 °C. The high performance of the doped films proved that the strategy of Nb doping in VO2 was promising for thermal-sensing applications.