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| 二氧化钒相变的太赫兹近场显微成像研究 |
| Terahertz near-field microscopy of vanadium dioxide phase transition |
| 投稿时间：2024-04-08 |
| DOI：10.3969/j.issn.1005-5630.202404080070 |
| 中文关键词: 太赫兹散射式扫描近场光学显微镜 二氧化钒单晶 二氧化钒多晶薄膜 非均匀相变 |
| 英文关键词:terahertz scattering-type scanning near-field optical microscopy vanadium dioxide single crystal vanadium dioxide polycrystalline film non-uniform phase transition |
| 基金项目:国家重点研发计划 (2017YFF0106304) |
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| 中文摘要: |
| 利用太赫兹散射式扫描近场光学显微镜（terahertz scattering-type scanning near-field optical microscopy，THz s-SNOM）表征分析了二氧化钒（VO2）单晶微米棒和多晶薄膜的热致相变过程。在样品升温过程中，VO2单晶的近场信号在344.9 K时发生突变，这是由于单晶内部结构的有序性使其能够迅速地从单斜结构变为四方金红石结构，从而表现出迅速且均一的相变；而VO2多晶薄膜在相变过程中则表现出成核的纳米岛生长并相互连接的现象，这可能是由于VO2多晶薄膜中存在晶界等缺陷导致了非均匀的相变。研究结果表明，THz s-SNOM系统具有在纳米尺度上灵敏探测材料电导率相对变化的能力，是对相变过程进行显微表征分析的有力工具。 |
| 英文摘要: |
| The thermoinduced phase transformation process of vanadium dioxide (VO2) single crystal micron rods and polycrystalline films was characterized and analyzed by terahertz scattering-type scanning near-field optical microscopy (THz s-SNOM). During the heating process, the near-field signal of VO2 single crystal changed abruptly at 344.9 K, 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. |
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