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过渡金属氧化物二氧化钒(VO2)在温度340 K附近会发生金属绝缘体的转变(metal-insulator transition,MIT).基于金属绝缘体的转变性质,VO2薄膜材料具有很好的应用前景.本文首先采用脉冲激光沉积制备了高质量的V2O5薄膜,再通过高温氢退火还原V2O5薄膜制备出VO2多晶薄膜.研究了不同的退火温度、退火时间、退火气氛对VO2薄膜制备的影响,采用X射线衍射、X射线光电子能谱、变温电阻特性测量等手段对样品进行分析,发现在H2(5%)/Ar退火气氛下,在一定的退火温度范围内(500—525 C),退火3 h,得到了B相和M相共存的VO2薄膜,具有M相的VO2的MIT特性,而相同退火温度下退火时间达到4.5 h,薄膜完全变成B相的VO2.通过纯Ar气氛下对B相VO2再退火,得到了转变温度为350 K,电阻突变接近4个数量级的M相的VO2薄膜.实现了VO2的B相和M相的相互转变.
Metal-insulator transition (MIT) occurs in the transition metal oxide vanadium dioxide (VO2) near the temperature of 340 K. Based on the transformation properties of the metal insulator, the VO2 thin-film material has a good application prospect.This paper first uses V2O5 thin films were prepared by pulsed laser deposition and VO2 polycrystalline thin films were prepared by high temperature hydrogen annealing reduction of V2O5 thin films.The effects of annealing temperature, annealing time and annealing atmosphere on the preparation of VO2 films were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, temperature resistance measurement and other means of analysis of the sample was found in the H2 (5%) / Ar annealing atmosphere, within a certain annealing temperature range (500-525 C), annealing 3 h, was VO2 thin films coexisting with phase B and M phase have the MIT characteristics of VO2 with M phase, and the annealing time reaches 4.5 h at the same annealing temperature, and the film completely becomes VO2 of phase B. The B phase VO2 is re-annealed , A VO2 thin film with an M transition temperature of 350 K and a sudden change in resistance of nearly 4 orders of magnitude has been obtained, which achieves the mutual transformation of phase B and phase M of VO2.