本論文研究氧化鎢(WO3)之各種不同奈米結構，並以鍛燒使材料表面粗糙化，製作成乙醇氣體感測器。吾人先透過射頻濺鍍系統沉積WO3種子層，再以水熱法成長氧化鎢奈米片(WO3 nanosheets)。實驗過程中添加封端劑(Capping agent)及酸性物質，分別聚合成氧化鎢奈米板(WO3 nanoplates)及氧化鎢奈米磚(WO3 nanobricks)等結構。藉由在P型矽基板上生長氧化鎢奈米結構，形成PN異質接面元件來感測其對乙醇氣體響應值之大小，並對元件進行物性與電性的分析。本研究主要討論氧化鎢材料所聚集而成的多種奈米結構，透過鍛燒改變元件表面形貌，進而提升乙醇氣體感測器的響應值。
加入封端劑讓奈米材料更加直立，提高元件之比表面積。而鍛燒處理能使奈米材料表面粗糙化，有利於對乙醇氣體之感測。實驗結果顯示，添加封端劑所成長的氧化鎢奈米板元件(WO3 nanoplate/P-Si)在鍛燒過後，對於400ppm乙醇氣體的響應值高達245.4%，為未經鍛燒元件的兩倍。其響應時間與恢復時間則分別縮短至14秒與12秒。因此，直立奈米結構加上鍛燒所形成之粗糙化材料表面，有利於提升感測乙醇氣體之響應度。

In this thesis, we discuss various nanostructures of tungsten oxide (WO3) and roughen the surface of nanomaterials with calcination for ethanol gas sensing applications. Firstly, the WO3 seed layer is deposited by RF sputtering system and the WO3 nanosheets are grown by hydrothermal synthesis. Capping agent and acid additive are added during the experiments to form WO3 nanoplates and WO3 nanobricks, respectively. Devices with p-n heterojunction are formed by growing WO3 nanostructures on p-type silicon substrates. The materials and the devices are investigated through different measurements to study their responses to ethanol gas. This research mainly discusses the aggregation of WO3 nanostructure and the surface morphology after calcination. The sensing ability of ethanol gas sensors are enhanced with additional processes.
Capping agent makes the nanomaterials more vertical and increases the surface-to-volume ratio of the devices. Calcination process roughens the surface of nanomaterials and is beneficial to gas detection. The experimental results show that the device fabricated with capping agent and calcination (WO3 nanoplate/P-Si) has a response of 245.4% to 400 ppm ethanol gas. This response value is twice higher than the sample without calcination. Besides, the response and the recovery times are shortened to 14 seconds and 12 seconds, respectively. As a result, vertical nanostructures and roughened surfaces have great potential to enhance the sensing response to ethanol gas.

誌謝................................................................................................................................. i
摘要................................................................................................................................ ii
Abstract ........................................................................................................................ iii
目錄............................................................................................................................... iv
表目錄.......................................................................................................................... vii
圖目錄........................................................................................................................ viii
第一章 緒論.................................................................................................................. 1
1-1 前言 ................................................................................................................................ 1
1-2 乙醇氣體介紹 ................................................................................................................ 1
1-3 乙醇感測器介紹 ............................................................................................................ 2
1-4 奈米結構 ........................................................................................................................ 3
1-5 氧化鎢 ............................................................................................................................ 3
1-5-1 氧化鎢的簡介與應用 ............................................................................................ 3
1-5-2 氧化鎢的感測原理 ................................................................................................ 4
1-6 論文架構 ........................................................................................................................ 5
第二章 理論分析.......................................................................................................... 6
2-1 粉末生長機制 ................................................................................................................ 6
2-1-1 水熱法 .................................................................................................................... 6
2-1-2 氧化鎢的製備 ........................................................................................................ 6
2-2 粉末形貌之改變 ............................................................................................................ 7
2-2-1 封端劑之影響 ........................................................................................................ 7
2-2-2 鍛燒之影響 ............................................................................................................ 7
2-3 氣體感測器工作原理 .................................................................................................... 8
2-3-1 工作溫度 ................................................................................................................ 8
2-3-2 PN異質接面氣體感測器 ....................................................................................... 9
2-3-3 乙醇氣體反應機制 .............................................................................................. 11
2-3-4 氣體響應度之定義 .............................................................................................. 11
2-4 薄膜成長儀器 .............................................................................................................. 13
2-4-1 射頻濺鍍機 .......................................................................................................... 13
2-4-2 熱蒸鍍機 .............................................................................................................. 14
2-5 量測儀器 ...................................................................................................................... 15
2-5-1 掃描式電子顯微鏡(SEM) .................................................................................... 15
2-5-2 X光繞射儀(XRD) ................................................................................................ 16
2-6 氣體量測系統 .............................................................................................................. 16
第三章 實驗步驟與量測機台.................................................................................... 18
3-1 材料選用 ...................................................................................................................... 18
3-2 感測器製程系統 .......................................................................................................... 19
3-2-1 射頻濺鍍系統 ...................................................................................................... 19
3-2-2 熱蒸鍍系統 .......................................................................................................... 19
3-3 感測器分析儀器與量測系統 ...................................................................................... 20
3-3-1 掃描式電子顯微鏡(SEM) .................................................................................... 20
3-3-2 能量散佈光譜儀(EDS) ........................................................................................ 20
3-3-3 X光粉末繞射儀(XRD) ........................................................................................ 21
3-3-4 氣體量測系統 ...................................................................................................... 21
3-4 製程步驟與成長參數 .................................................................................................. 22
3-4-1 矽基板清洗步驟 .................................................................................................. 22
3-4-2 濺鍍沉積氧化鎢薄膜種子層 .............................................................................. 23
3-4-3 水熱法生長氧化鎢奈米片結構........................................................................... 23
3-4-4 水熱法生長氧化鎢奈米板結構........................................................................... 23
3-4-5 水熱法生長氧化鎢奈米磚結構........................................................................... 24
3-4-6 蒸鍍鋁電極 .......................................................................................................... 25
第四章 結果與討論.................................................................................................... 26
4-1 物性分析 ...................................................................................................................... 26
4-1-1 氧化鎢水熱時間對形貌之比較........................................................................... 26
4-1-2 氧化鎢奈米片生長結果與分析........................................................................... 26
4-1-3 氧化鎢奈米板生長結果與分析........................................................................... 27
4-1-4 氧化鎢奈米磚生長結果與分析........................................................................... 28
4-2 奈米結構生長機制分析 .............................................................................................. 29
4-2-1 奧斯特瓦爾德熟成(Ostwald Ripening) ............................................................... 29
4-2-2 封端劑與添加劑之生長機制分析....................................................................... 29
4-3 電性分析與探討 .......................................................................................................... 30
4-3-1 氧化鎢奈米片元件之分析與探討....................................................................... 30
4-3-2 氧化鎢奈米板元件之分析與探討....................................................................... 31
4-3-3 氧化鎢奈米磚元件之分析與探討....................................................................... 32
4-4 元件動態響應與選擇性分析 ...................................................................................... 34
4-4-1 氧化鎢奈米片元件之分析 .................................................................................. 34
4-4-2 氧化鎢奈米板元件之分析 .................................................................................. 35
4-4-3 氧化鎢奈米磚元件之分析 .................................................................................. 35
4-5 最佳元件之探討 .......................................................................................................... 36
第五章 結論與未來展望............................................................................................ 37
5-1 結論 .............................................................................................................................. 37
5-2 未來展望 ...................................................................................................................... 38
參考文獻...................................................................................................................... 39
附表.............................................................................................................................. 43
附圖.............................................................................................................................. 46

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