隨著科技日新月異，近年來應用半導體薄膜於氣體感測非常廣泛，其中氧化鎵在高溫下穩定且具有N型半導體特性，更常被應用於感測還原性氣體。因此本研究利用真空蒸鍍熱氧化法製備氧化鎵薄膜氣體感測器，並探討不同氧化時間、不同膜厚下之半導體特性。進一步針對此變因探討氧化鎵薄膜之奈米線的成長，以及對氣體感測的影響。

　　實驗結果顯示，鎵薄膜在高溫下長時間氧化會使表面晶粒大小有變小的趨勢且大小逐漸均勻。當氧化時間增加時，Ga2O3的半導體特性會由N型半導體特性轉變為P型半導體特性。

　　1.0μm鎵的氧化鎵薄膜有一最佳感測溫度為575℃，且氧化氣氛在流通酒精蒸氣下氧化時奈米線成長最多且最長。0.2μm鎵薄膜沒有奈米線的產生，與實驗室之前的研究結果相符；2.0μm鎵薄膜因使用較低的蒸鍍速率而使得蒸鍍時間較長，造成薄膜較緻密且產生較高的結晶度，以致於無法產生奈米線。

　　氧化鎵薄膜在不同膜厚（0.2μm、1.0μm和2.0μm）及不同感測溫度（550℃、575℃和600℃）下進行感測，靈敏度皆隨感測氣體濃度增加而增加。

　　In recent years thin film semiconductor is extensively used as gas sensor to detect poison gas. And Ga2O3 possesses an N-type semiconductor characteristic, is stable at high temperature and being most often applied in detecting reducing gas. In the current study, Ga2O3 semiconductor thin film was prepared by rtheotaxial growth and thermal oxidation (RGTO) method on SiO2. The morphology and the electrical properties of Ga2O3 films were measured as functions of the thickness of Ga deposited on SiO2 and oxidation time. Their effects on the growth of nanowires of the Ga2O3 were examined.

　　The experimental results show that Ga2O3 grain size decreases as the oxidation time increases at high temperature, and the film morphology became uniform. When the oxidation time increases, the semiconductor characteristic of the Ga2O3 changes from N-type to P-type.

　　The sensitivity of the Ga2O3 films in response to ethanol were found to have an optimum sensing temperature at 575℃. Long nanowires are produced, however highest density of nanowires is observed if the oxidation is carried out under the ethanol vapor flow. When the thickness of Ga2O3 is below 0.3μm, no nanowires will be produced, and the same result was observed in this study.

　　Theoretically, an increase of concentration of reactant vapor must lead to more shifting of the resistance, and the identical experiment result agree with the theoretical prediction.

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