| 초록 |
Vanadium dioxide (VO2), strongly correlated materials, has been generally believed that the metal-insulator transition (MIT) is driven by either strong electron-electron interaction (Mott transition), electron-phonon interaction (Peierls transition), or a combination of both mechanisms at a critical temperature of ~68oC. VO2 has received considerable attention because of a variety of possible applications based on its MIT such as Mott field transistors, electrical-optical switching devices, phase-change memories, and bolometric sensors. The transition of VO2 can be also driven by strain, pressure, doping, size effect, etc. Accordingly, there have been many studies to understand the influences of such factors individually. However, there has been no report investigating the correlation of multiple factors because of the difficulty in controlling the MIT simultaneously. Here, we report the correlation between hydrostatic pressure and external stress induced by electrode-clamping on MIT properties of VO2 nanowires. The insulator to metal transition temperature of the nanowire increases with thickness of electrodes deposited on both ends of the wire as the ambient pressure decreases and this trend became more dramatic below 1 Torr. Specifically, the transition temperature increases to 470oC from 180oC and also the hysteresis in temperature became wider. Therefore, our study may provide helpful information on understanding the interaction of the factors inducing MIT and exploiting these factors for applications such as bolometric sensors, especially in space. |
