材料科学
X射线光电子能谱
金属-绝缘体过渡
相变
退火(玻璃)
大气温度范围
相(物质)
转变温度
分析化学(期刊)
金属
凝聚态物理
化学工程
热力学
冶金
化学
超导电性
物理
工程类
有机化学
色谱法
作者
Kaneyasu Nishikawa,Masamichi Yoshimura,Yoshihide Watanabe
出处
期刊:Journal of vacuum science & technology
[American Vacuum Society]
日期:2022-03-07
卷期号:40 (3)
被引量:5
摘要
Vanadium dioxide (VO2) exhibits a metal-insulator phase transition at approximately 70 °C. Two different crystal structures, M1 and M2 phases, in the insulating state have been reported. The M2 phase is expected to be a Mott insulator, whereas the M1 phase is expected to act as a band insulator. It is important to clarify the origin and transition properties of the M2 phase. In this study, we fabricated VO2 nanostructures via sputtering deposition and subsequent lamp annealing at various O2 pressures. Temperature-dependent XRD measurements revealed that the nanostructured VO2 exhibits the M2 phase in temperatures just before the phase transition from M1 to R (metal state) during the heating process. The ratio of V5+/(V4+ + V5+) in nanostructured VO2 was estimated from XPS results; an increase in this ratio resulted in the broadening of the temperature range of the M2 phase. Furthermore, in the cooling process, direct phase transitions from R to M1 were observed. Structural changes are likely to occur in different pathways during heating and cooling. Our findings should contribute to the identification of the phase transition mechanism and to the development of a Mott field-effect transistor that utilizes nanostructured VO2 in the M2 phase.
科研通智能强力驱动
Strongly Powered by AbleSci AI