VO2(A)型薄膜表面形貌与相变性能的相关性

Relativity between Surface Morphology and Phase Transition Performance of VO2(A) Thin Film

摘要:

以高纯五氧化二钒（V2O5）粉末(纯度≥99.99%)为原料，采用真空蒸发——还原工艺制备出VO2(A)型薄膜(A表示发生热致相变的薄膜)。讨论退火温度对VO2(A)型薄膜表面形貌的影响，并进一步研究表面形貌与薄膜光电性质的相关性。结果显示：当退火温度从500 ℃升高到540 ℃，VO2(A)型薄膜中层状特征减弱并消失，山峰状颗粒出现并增大，当退火温度继续升高，VO2(A)型薄膜中山峰状颗粒是先减小再增大，但是其尺寸趋于一致，约为50 nm；随着 VO2(A)型薄膜形貌的改变，相变温度点、数量级、热滞回线宽度等相变性能参数也会改变；VO2(A)型薄膜相变温度点降低，其在所测波段的透过率会降低，但只有在中红外波段，薄膜在相变前后透过率的改变量与电阻变化的数量级有关。

Abstract:

The VO2(A) thin films with the property of the thermochromic phase transition were prepared by vacuum evaporation deoxidization technology with the V2O5 powders (purity≥99.99%) as starting materials. The morphology of the VO2(A) thin films were studied, which were affected by the annealing temperature, and its effects on the optical properties and electrical properties were also studied. The results show that the stratiform characteristics are weakened until disappear and the peak-like particles appear and become large when the annealing temperature increases from 500 oC to 540 oC; however, the peak particles diminish firstly and then become large when the annealing temperature continues to increase, but the sizes of the particles become similar, about 50 nm. With the alteration of the morphology, the parameters of the phase transition, such as the critical temperature, the order of magnitude and the hysteresis loop width will change correspondingly. As the critical temperature decreases, the transmission of the thin films will decrease correspondingly, but only the transmission in the middle infrared during the phase transition changes correspondingly to the order of magnitude.