有鑑於台灣的工業區林立，加上周圍大多是住商混合區，對於排放氣體方面，必須要有即時性的環境監測，以達到預警效果。氧化鎵材料在高溫環境下展現半導體性質與高穩定性，並對還原性氣體具感測性質。本研究以電漿增強化化學氣相沉積、物理氣相沉積及水蒸汽熱氧化法在石英基板上製備出碳/氧化鎵與鎵/氧化鎵薄膜氣體感測器。針對兩種複合膜，改變其鍍膜先後順序、厚度及有無經過高溫程序，探討其表面形態、電性、晶相結構以及元素組成。
實驗結果顯示，當碳膜層在底層，鎵膜在上層一起進行水蒸汽熱氧化法後，並不會影響氧化鎵的表面型態。當碳為底層時，對感測性沒有明顯提升，甚至有減少的趨勢，而當氧化鎵在底層，碳或鎵膜層在上層時，對氧化鎵的晶相沒有影響，但可提升感測度。氧化鎵薄膜上鍍上鎵膜層時，其薄膜可有效縮短其響應時間至5~20秒內，其最佳響應時間比氧化鎵/碳薄膜加快了將近4倍。

Gallium oxide possesses the property of the semiconductor which is stable at high temperature, and has been applied in detecting reducing gas recently. In this study, a layer of Carbon/Gallium was deposited on top of Ga2O3 film (C/Ga2O3 and Ga/Ga2O3) or a layer of carbon under Ga2O3 film (Ga2O3/C) via a series of steps: plasma enhanced chemical deposition(PECVD) , physical vapor deposition(PVD) and rheotaxial growth and thermal oxidation (RGTO) with water vapor. The morphology, crystalline structure, element ratio and electrical property of C/Ga2O3 and Ga/Ga2O3 were measured as functions of the position of carbon film, the thickness of gallium and the condition of annealing. The experimental results show that carbon film position has no effect upon the surface morphology, and the sensitivity of Ga2O3/C thin film doesn`t increase obviously. However the deposition of carbon film or gallium film on top of Ga2O3 film increases the sensitivity obviously, and has no effect upon the Ga2O3 crystalline structure. The response time of Ga/Ga2O3 thin film reduces to 5~20 seconds. The response of Ga/Ga2O3 is much faster than Ga2O3/C thin film.

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