High temperature coefficients of resistance of VO2 films grown by excimer-laser-assisted metal organic deposition process for bolometer application

With bolometer application in mind, we prepared VO2 films on TiO2 (001) substrates by an excimer-laser-assisted metal organic deposition process at 300 °C or less. A metal-to-insulator transition of VO2 is expected to induce high temperature coefficient of electrical resistance (TCR) useful for high-performance infrared sensors, but the practical use of crystalline VO2 films has been prevented due to the accompanied wide hysteresis. In this study, by forming the epitaxial phase only near the substrate interface, the transition of the film was successfully broadened and the hysteresis disappeared. The maximum TCR of the film was more than –10%/°C near room temperature, and the temperature range in which TCR was higher than –4%/°C was very wide (280–320 K).