Direct evidence for the coexistence of nanoscale high-conduction and low-conduction phases in VO2 films
Direct evidence for the coexistence of nanoscale high-conduction and low-conduction phases in VO2 films
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VO2 薄膜中纳米级高导相和低导相共存的直接证据
DOI：
10.1063/1.5032270
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发表时间：
2018-10-22
影响因子：
4
通讯作者：
Liu, J-M
中科院分区：
文献类型：
--
作者：
Feng, Jiajun;Yang, Cheng;Liu, J-M
A systematic investigation of the nanoscale conduction behavior of vanadium dioxide (VO2) films deposited on aluminum oxide (Al2O3) substrates, using conductive atomic force microscopy, is presented. Aside from the macroscale resistance-temperature characteristics, which show a steep insulator-metal transition at the transition point Tm ∼ 68 °C, our experiments demonstrate a coexistence of nanoscale high-conduction and low-conduction phases over a broad temperature window (50 K range) across the Tm. In addition, the area (volume) fraction of the high-conduction phase increases with increasing temperature across the transition point. The current-voltage data obtained on a nanoscale indicate that the high-conduction phase is not a good metal. When the temperature increased across the Tm, the probed charge transport behavior of the high-conduction phase is found to change from a mechanism dominated by space-charge limited current to a mechanism dominated by Schottky emission.
