- 期刊
室溫型一維二氧化釩奈米線之光致相變特性研究
Study on The Photo-induced Phase Transition Property of One Dimensional VO2 Nanowires in Room Temperature
摘要
二氧化釩（Vanadium Dioxide, VO2）為一種多功能的氧化物材料，具備金屬-絕緣相轉變特性，在相轉變時會導致物理性質的改變，可應用於智能的感測元件上，本實驗利用五氧化二釩（V2O5）粉末以熱蒸鍍法方式還原成二氧化釩奈米線，經由場發射掃描式電子顯微鏡（Field Emission Scanning Electron Microscope, FESEM）、高解析穿透式電子顯微鏡（High-ResolutionTransmission Electron Microscopy, HRTEM）、X光繞射儀（X-Ray Diffractometer, XRD）與拉曼光譜儀（Raman Spectroscopy, Raman）進行置備的材料分析，並研究其光致相變特性，本研究以紫外燈光（λ=254 nm）照射二氧化釩奈米線，使得二氧化釩奈米線由單斜晶轉變為正方晶相，研究發現在照射紫外光下，二氧化釩能帶結構由原本分裂的dïï能帶，會結合成一個能帶並與π能帶部分結合，最後費米能階會落在兩能帶之間，使得二氧化釩由半導體相轉變為金屬相導電率因此提升，反應與回復時間在1秒內。
並列摘要
Vanadium dioxide (VO2) is a multi-functional oxide material. It exhibits a phase transition from metal-to-insulator. Therefore, the VO2 can be applied on smart sensing device. In this experiment, the thermal evaporation method was employed to synthesize the VO2 nanowires. To investigate the photo-induced phase transition properties of as-synthesized products, VO2 nanowires was examined by the field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffractometer (XRD), Raman spectroscopy, and ultraviolet (λ= 254nm) lights system. The VO2 nanowires occurs phase transition from monoclinic to tetragonal under ultraviolet-light irradiation (λ=254nm). The energy band of VO2 exhibited that two splitting dïï band were combined into a single band, which then merged with the partial π* band. Therefore, the Femi-level positions at these two bands, resulting in increasing the conductivity of VO2 nanowires. The response and recovery time are less than 1 sec.