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  • 學位論文

表面聲波元件紫外光及室溫下有機氣體感測器之研發

Application of SAW Device sensor for UV light and Organic Gas at room temperature

指導教授 : 馬劍清

摘要


表面聲波元件為一種現代感測器廣泛應用的元件,其具有高敏感度、體積小、質量小及設計與製造簡單等優勢,因此可利用微機電製程大量製造,已應用於感測溫度、濕度、壓力、液體黏滯性及氣體濃度等等之感測器,近年來已有相當多的市售產品與研究成果發表。除了感測器外,也由於其中心頻率的能量相當明顯,亦可在通訊方面為濾波器使用,可為生活帶來更多便利性。 表面聲波元件主要由壓電基板、指叉電極、感測區三者所構成,在本文中首先建立表面波基本理論模型,並且選擇鈮酸鋰128Y-cut壓電基板製作表面聲波元件,探討各種元件設計對於中心頻率、頻率響應及插入損失的影響,並與理論進行比較。本研究亦利用氧化鋅的光電特性與表面聲波元件間產生聲電耦合效應,製作紫外光感測器,於元件之延遲線上感測區濺鍍約2000 A之氧化鋅薄膜,當氧化鋅受紫外光照射時會產生電子躍遷使得表面電子增加而使延遲線上導電度改變進而影響元件所接收之訊號,並配合光功率計之使用,顯示本研究製作之元件於高光強下照射波長360nm之紫外光有最大的感測效果,並於在330~390nm間都具有相當實用之線性感測效果。 鑑於近年酒駕事件頻傳,本研究進一步利用氧化鋅照射紫外光後所躍遷之電子會與有機氣體產生化學反應,導致表面電子減少而影響延遲線上導電度之現象製作酒精有機氣體感測器,以10ppm及100ppm濃度之酒精作為研究目標,顯示本研究所製作之有機氣體感測器有高敏感度,可感應到低於10ppm之酒精氣體感測,且加長照光時間可增強其感測能力。 本研究中將各種不同元件設計對紫外光及有機氣體感測能力之影響原因皆詳細討論,並利用微機電製程將各元件製作完成量測並加以分析比較,以期對於表面聲波元件感測器有更進一步了解,發展最佳化設計方法以及製程。

並列摘要


SAW devices are wildly used in recent years for the advantages of sensitive, simple, small and can be manufactured easily. In this research, SAW device is used as the UV and organic gas sensors. In the sensor system, IDT is developed on the surface of piezoelectric substrate LiNbO3 128Y-cut. The center frequency measured by the device is compared with the impulse-function model. In general, the center frequency, insertion loss or surface velocity of SAW device is affected by acoustoelectronic interaction and mass loading. Therefore, we use the sensing material Zinc-Oxide, that can generate photoelectric effects with UV light, to develop as the UV sensor. In this research, a SAW device with 2000A Zinc-Oxide membrane sputtered on sensing area is fabricated, the light wavelength between 330nm to 400nm is analyzed, and a sensitivity in the order of is found. It shows the best sensing ability is found to be the wavelength of 360nm and strong intensity of light. The car accidents of driver with intoxicated are raising rapidly, this research use the fact that Zinc-Oxide can react with organic gas under UV light to develop the organic gas sensor. From the experimental measured results, the SAW organic sensor has excellent sensitivity even under 10ppm concentration of ethanol gas. The better sensing ability is achieved by longtime illuminated under UV light.

並列關鍵字

Saw device ZnO UV light Organic gas Ethanol

參考文獻


黃采如,馬劍清, “表面聲波元件應用於光感測器之設計、分析與量測,”博士論文,機械工程學研究所,臺灣大學, 2007
余志明,馬劍清, “寬頻表面聲波元件於陣列式光感測器之應用,”碩士論文,機械工程學研究所,臺灣大學, 2006
蔡奇儒,馬劍清, “表面聲波元件理論模擬以及溫濕度與紫外光波段感測器研發,”碩士論文,機械工程學研究所,臺灣大學,2011
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