[2Bp01-10] Surface Analysis/Applied Surface Science/Evaluation Technique (ASS)

[2Bp09] The effect of Ar⁺ ion irradiation on metal-insulator transition of VO₂ film fabricated on Si substrate

*Kazutaka Nishikawa¹, Masamichi Yoshimura¹, Yoshihide Watanabe¹ (1. Toyota Technological Institute)

Vanadium dioxide (VO₂) undergoes metal-insulator transition at around 70 ºC. While various applications using VO₂ material have been proposed, it is important to control the thermal hysteresis width of VO₂. In this study, we found that the Ar⁺ ion irradiation with 1 keV reduces the thermal hysteresis width of VO₂. We prepared the VO₂ film with the thickness of 80 nm on Si substrate via thermal oxidation of V film. Ar⁺ ion irradiation with the acceleration energy of 1 keV was performed on VO₂ film under 3×10^-6 Pa. The temperature-dependent reflectivity measurements showed that the thermal hysteresis width decreased by 15 °C after Ar⁺ ion irradiation. Moreover, soft X-ray absorption measurements at a synchrotron radiation facility revealed that oxygen deficiencies are introduced on the surface of VO₂ film after Ar⁺ ion irradiation. Therefore, the obtained results in this study suggested that the thermal hysteresis width of VO₂ film can be controlled by the oxygen deficiency.