一維氧化鎢奈米材料應用於NO2氣體感測特性之研究

本研究係利用直流磁控濺鍍系統配合紅外線加熱爐之退火處理於氧化鋁基板上製備一維氧化鎢奈米材料，並分別探討固定1 Wcm-2功率密度，濺鍍時基板的溫度(25℃、250℃)、鎢薄膜厚度(150 nm、300 nm、500 nm)以及真空中700℃退火處裡之持溫時間(1 hr、2 hr)對材料表面形貌、結構、化學成分及NO2氣體感測特性的影響。研究中發現，隨著退火溫度升高，薄膜會開始成核成長逐漸轉變為一維奈米結構，且若於沉積鎢薄膜時，將氧化鋁基板加熱至250℃，並持溫至濺鍍製程結束，對退火處理後成長之氧化鎢奈米線長度有明顯變長之趨勢。經微結構分析得知，本實驗製備的一維氧化鎢奈米材料為W18O49單斜晶系之相態，晶格成長方向是延著(010)晶面成長，並由HRTEM的結果得知晶格間距為0.378 nm，與XRD結果相符。藉由Raman光譜儀進行光學特性分析，發現在波數為200~500 cm-1及500~1000 cm-1之間有明顯的拉曼光譜線出現，與標準拉曼光譜比對後的判定Monoclinic 的氧化鎢。本研究製備的一維氧化鎢奈米材料，NO2氣體感測結果顯示，在最佳工作溫度150℃下，對不同濃度(10~100 ppm)之NO2氣體進行檢測，發現經基板加熱過後生成之氧化鎢奈米線具有最佳感測性質，且隨著濃度的增加靈敏度(S = 2.22至3.13)也會呈現線性成長。

關鍵字

磁控濺鍍；熱退火；氧化鎢；氣體感測

並列摘要

In this study, the one-dimension tungsten oxide nanomaterials were prepared using DC magnetron sputtering, followed by annealing treatment. We adjusted various fabricated parameters such as the stable power dessity (1 Wcm-2), substrate heating (25-250℃), thickness of thin films (150, 300 and 500 nm) and annealing duration (1-2 hr) to investigate their impact on the morphology, phase, microstructure and NO2 gas sensing. During this research, we observed that the tungsten thin films which the heating substrate at 250℃ was a better preparation way for nanowire than them without substrate heating, and they were synthesized to transform into an one-dimensional structure of tungsten oxide with annealing treatment of 700℃. The length of nanowires gradually increased with longer annealing duration time, and the diameter of nanowires also had good growth trend. The results of microstructure analysis indicated that the one-dimension tungsten oxide nanomaterials present W18O49 phase with (010) growth plane. After HRTEM analysis, the d-spacing of (010) plane was 0.378 nm. In Raman analysis, we observed that the Raman spectrum of tungsten oxide nanowires appeared Raman shift at two main regions (200~500 cm-1 and 500~1000 cm-1). It indicate that the W18O49 nanowires were monoclinic structure. In gas sensing results, we found out the optimum working temperature of 150℃, and using different concentrations (10~100 ppm) to do experiments for NO2 gas sensing properties, and found out the nanowire with substrate heating had the best sensing properties. Finally, we got the conclusion that gas sensing sensitivity (2.22 to 3.13) increased with the concentration also showed a linear growth.

並列關鍵字

Magnetron Sputtering ； Annealing ； Tungsten Oxide ； Gas sensing

參考文獻

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一維氧化鎢奈米材料應用於NO2氣體感測特性之研究

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