운모 기판 위에 증착된 VO₂ 박막의 결정성과 금속-부도체 상전이 특성

Mica substrates, as layered materials, can be exfoliated into thin layers, making them suitable substrates for the fabrication of flexible films. VO2 is a material that exhibits a significant change in optical transmittance alongside its metal-insulator transition (MIT). Therefore, VO2 thin films deposited on mica substrates can be utilized for the development of flexible optoelectronic devices. In this study, VO2 thin films were grown on thin and smooth mica substrates using the pulsed laser deposition (PLD) method. The structural and electrical properties were systematically analyzed by varying the oxygen partial pressure, deposition temperature, and film thickness. When the VO2 films were deposited at an oxygen partial pressure of 5-15 mTorr and a deposition temperature of 500-650 ^◦C, excellent (010)-oriented crystal growth and MIT properties were observed. Since the mica substrate started to deform at temperatures above approximately 600 ^◦C, the optimal deposition condition was determined to be a deposition temperature of 550 ^◦C and an oxygen partial pressure of 10 mTorr. Furthermore, as the film thickness decreased, the MIT temperature showed a tendency to decrease due to surface defects, while films thicker than 35 nm exhibited nearly constant MIT characteristics. This study provides optimal deposition conditions for VO2 thin films on mica substrates, serving as an important foundation for flexible optoelectronic device applications.