本實驗以三氧化鉬粉末作為前驅物，利用熱蒸鍍法搭配氬氣當載流氣體在矽基板合成氧化鉬奈米線，並透過改變各項參數探討奈米線形貌的變化，分析出最佳的生長參數，接著再透過電化學中的定電流法將銀奈米顆粒修飾在氧化鉬奈米線表面，並透過SEM、XRD、TEM、EDS、XPS，來觀察表面形貌及鑑定結構與成分，並且量測單根奈米線的電阻率進行比較，結果表示無修飾的氧化鉬奈米線的電阻率為7.6＊10-7Ω·m，擁有最低的電阻率，優於文獻值，因奈米線存在適量氧空缺可以使電子傳輸性質優化，且發現修飾銀奈米顆粒會導致電阻上升，但此特性有助於氣體感測性質的提升。最後將奈米線和修飾兩種不同比例銀顆粒的奈米線去進行氣體感測實驗，本實驗的感測氣體為20ppm的二氧化碳、丙酮、乙醇氣體，結果發現隨著操作溫度上升，奈米線對感測氣體的響應越佳，且5%Ag-氧化鉬奈米線有最好的感測效果，本實驗合成之奈米線對二氧化碳氣體有最佳的響應，300℃下響應程度可達到72.4，其次是丙酮及乙醇氣體，響應程度可達到39.2及30.1。

In this experiment, molybdenum trioxide powder was used as the precursor to synthesize molybdenum oxide nanowires on a silicon substrate through thermal evaporation and argon as the carrier gas. In the second part, the silver nanoparticles were decorated on the surface of the molybdenum oxide nanowire by the constant current method in electrochemistry. The surface morphology and the microstructure of two kinds of nanowires were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS). Comparing with the composition and measuring the resistivity of a single nanowire, the result shows that the resistivity of the unmodified molybdenum oxide nanowire is 7.6*10-7Ω·m. Due to the existence of a proper amount of oxygen vacancies in the nanowires, the electron transport properties can be optimized. Finally, the nanowire and the nanowire modified with two different proportions of silver nanoparticles are used for gas sensing experiments. The sensing gas in this experiment is 20ppm of carbon dioxide, acetone, and ethanol. The results show that as the operating temperature rises, the nanowire has a better response to the sensing gas. The 5% Ag-molybdenum oxide nanowire has the best sensing effect. The nanowire synthesized in this experiment has the best response to carbon dioxide gas. The response to carbon dioxide gas at 300°C can reach 72.4 and the response to acetone and ethanol gas can reach 39.2 and 30.1.

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