本研究使用熱蒸鍍法以三區水平式爐管配合高載流氣體，在不使用催化劑之情況下成長出具有優良高寬比之氧化鎢奈米線，調控參數為載流氣體之種類，目的為不影響整體環境壓力及氣體流量的限制下改變氧分壓，並觀察氧化鎢奈米線產生之各種變化。共使用三種參數，(1)載流氣體使用氬氣，流量為100 sccm，氧分壓為0.02 torr，化學式為WO2.7725；(2) 載流氣體使用氧氬混合氣體(O2 50% + Ar 50%)，流量為100 sccm，氧分壓為0.16 torr，化學式為WO2.81；(3) 載流氣體使用氧氣，流量為100 sccm，氧分壓為0.3 torr，化學式為WO2.838。
三種參數製成之氧化鎢奈米線在形貌、晶格方面並無二致，三者差別在於晶格缺陷之多寡。在氧分壓介於0.02 torr及0.3 torr之間時，提高氧分壓將會降低氧空缺之數量，可以控制氧分壓來決定氧空缺之數量，但使用氧氬混合氣體時氧化鎢奈米線會產生大量表面缺陷，推測其原因為通入氧氬混合氣體會使奈米線成長過程中產生內部應力，在持溫結束後之退火會使應力釋放，奈米線晶格緩慢重新排列。
量測三種參數之奈米線的性質後可發現：氧化鎢奈米線表面之缺陷數量對導電性及光催化表現有幫助。缺陷越多，電子在物質中移動所需之能量越低，故導電性提升。在光催化方面，缺陷能使吸附有機汙染物的效率提升進而使光催化效率提升及降低電子電洞對再結合速度，使光催化表現提升。

In this study, we successfully synthesized tungsten oxide nanowires contain abundant of oxygen vacancies by three-zone furnace tube via thermal evaporation method without any catalyst. By alternating the oxygen pressure, the quantity of oxygen vacancies in tungsten oxide nanowires would change, therefore influence the properties of nanowires like electrical conductivity and performance of photodegradation. To learn more about the morphology and phases, we use scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and electron energy loss spectroscopy (EELS). The results show that there’s no significant change in morphology and phases, only the quantities of oxygen vacancies increase when oxygen partial pressure gets lower. It can help us understand the difference of NWs with different quantities of oxygen vacancies. NWs synthesized under PO2 = 0.3 torr has better crystallinity due to the reduction of oxygen vacancies, may increase the life time of electrochromism application. NWs synthesized under PO2 = 0.02 torr & 0.16 torr with higher quantities of defects, their electrical conductivities and efficiencies of photodegradation are better than better than NWs synthesized under PO2 = 0.3 torr. Single nanowire synthesized under PO2 = 0.16 torr has a low resistivity ρ = 5.492x10-5 m-Ω; Single nanowire synthesized under PO2 = 0.16 torr has a low resistivity ρ = 9.731x10-6 m-Ω. Also, These NWs have photocatalytic performances toward methylene blue that are two times better than NWs synthesized under PO2 = 0.3 torr. They are applicable to elimination of organic pollutants in the environment.

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