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二氧化钒(VO_2)是一个传统的具有不同晶型的二元化合物。由于金红石结构的VO_2最为稳定,且在340K附近具有半导体-金属相变(SMT)特性,因此引起人们的广泛关注。在340K时,该材料由单斜结构转变为四方结构,实现从半导体相到金属相的转变。此外,该转变温度(τ_c)也可通过掺杂钨元素降低至室温。这种特性使VO_2有望成为一种节能的“智能窗”功能材料,广泛应用于莫特场效应晶体管和光电开关装置。SMT的特性可以理解为晶格的扭曲可消除能带简并性,从而使电子相关能形成完美的窄带。许多研究人员主要研究与SMT相关的电、磁和光学特性的可逆突变。本文通过测量水介质中纳米棒电位变化,观察与VO_2纳米棒的半导体-金属相变相关的表面电荷的可逆变化。TEM结果的模拟也显示存在类似可逆变化。
Vanadium dioxide (VO 2) is a traditional binary compound with different crystalline forms. Since the VO 2 of rutile structure is the most stable and has the properties of semiconductor-metal phase transition (SMT) near 340K, it has aroused people’s attention. At 340K, the material is transformed from a monoclinic structure to a tetragonal structure, transforming from the semiconductor phase to the metal phase. In addition, this transition temperature (τ_c) can also be reduced to room temperature by doping tungsten. This feature makes VO_2 an energy-efficient “smart window” functional material that is widely used in Mott FETs and optoelectronic switching devices. The characteristic of SMT is that the distortion of the crystal lattice can eliminate the degeneracy of the band so that the electron correlation can form a perfect narrow band. Many researchers mainly study reversible mutations of SMT-related electrical, magnetic, and optical properties. In this paper, the reversible changes of surface charges related to the semiconductor-metal phase transition of VO_2 nanorods were observed by measuring the potential changes of nanorods in aqueous media. Simulations of TEM results also show similar reversible changes.