二氧化钒相变的太赫兹近场显微成像研究

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中图分类号：O433文献标志码：A

Abstract： The thermoinduced phase transformation process of vanadium dioxide （VO2） single crystal micron rods and polycrystalline films was characterized and analyzed by terahertz scatering-type scanning near-field optical microscopy （THz s-SNOM）.During the heating process， the near-field signal of VO2 single crystal changed abruptly at 344.9K， which was due to the orderliness of the internal structure of the single crystal， which enabled it to rapidly change from monoclinic structure to tetragonal rutile structure， showing rapid and uniform phase transition. While the VO2 polycrystalline film exhibited the phenomenon of nucleated nanoisland growth and interconnection during the phase transition， which was due to the existence of defects such as grain boundaries in the VO2 polycrystalline film， resulting in non-uniform phase transition. The results show that the THz s-SNOM system has the ability to sensitively detect the relative change of conductivity of materials at the nanoscale，and is a powerful tool for microscopic characterization and analysis of the phase transformation process.

Keywords： terahertz scatering-type scanning near-field optical microscopy; vanadium dioxide single crystal; vanadium dioxide polycrystalline film; non-uniform phase transition

二氧化钒（ VO2 ）的相变特性自1959年被首次报道以来就受到了广泛的关注[1。（剩余10919字）