臺灣博碩士論文加值系統

奈米碳管(carbon nanotube, CNT)具有優異的電性，所以奈米碳管電晶體具有相當大的潛力應用於未來的奈米電子元件。在本研究中以本實驗室發展的SiO2/Ni構成的雙層催化劑結構為基礎，在二氧化矽基版上蒸鍍催化劑，再經由高溫化學氣相沉積(Thermal Chemical Vapor Depositon, Thermal CVD)的方式成長單壁奈米碳管，進一步製作成奈米碳管場效電晶體(CNT-FET)。此方法能有效的定位奈米碳管，並能由雙層催化劑的鍍率控制奈米碳管的密度、長度以及直徑。
在本研究中，採用波長分別為488 nm、632.8 nm、785 nm之激發源，量測背閘極奈米碳管場效電晶體之光電流。在背閘極元件量測上，需施加適當的閘極偏壓，減少電子堆積於Si/SiO2界面，避免出現photogating現象；所量測的元件對波長為632.8 nm之激發源轉換效率最佳，達到4.93×10-7，經量測碳管直徑後研判使用之激發源激發了碳管的第二激發態，且光電流大小與汲極偏和激發源強度成線性關係。
在懸空結構元件的製作上，採用先行製作蝕刻溝槽，並在電極上蒸鍍催化劑後，直接成長單壁奈米碳管於金屬電極上，成功跨長奈米碳管於深1 μm、寬8 μm的溝槽，完成懸空元件的結構。
在懸空元件電性量測上，懸空奈米碳管元件因閘極調變能力不佳，有效的避免了photogating效應；在光電流的量測上，懸空結構減少了SiO2基版捕捉碳管中的載子，轉換效率約為10-4，有效的增強了電信號之強度。

摘要 I
誌謝 III
目錄 VI
圖目錄 VIII
表目錄 XIV
第一章 緒論 1
1-1 奈米碳管的材料結構與能態 1
1-2 奈米碳管場效電晶體 4
1-2-1 奈米碳管場效電晶體的結構 4
1-2-2 奈米碳管場效電晶體的工作原理 7
1-2-3 奈米碳管場效電晶體的傳輸特性 9
1-3 奈米碳管的光學性質 11
1-3-1 光致發光 11
1-3-2 電致發光 12
第二章 文獻回顧 15
2-1單根奈米碳管的光導現象 15
2-2 氣體分子吸附與光電流 19
2-3 photogating效應 21
2-4 懸空奈米碳管的電性及光學特性 23
2-4-1 懸空奈米碳管元件的製作及電性 23
2-4-2 懸空奈米碳管的光學特性 28
2-5 懸空奈米碳管的光導現象 30
2-5-1 部分懸空奈米碳管元件光導現象 30
2-5-2 懸空奈米碳管薄膜的光導現象 32
2-6 研究動機 33
第三章 研究方法與實驗設備 35
3-1 研究方法 35
3-2 試片製備 36
3-2-1 背閘極奈米碳管場效電晶體試片製備 36
3-2-2 懸空奈米碳管元件試片製備流程及光罩圖形 39
3-3 實驗設備 42
3-3-1 高溫化學氣相沉積系統(Thermal CVD) 43
3-3-2 掃瞄電子顯微鏡(Scanning Electron Microscopy) 45
3-3-3 電子束微影設備(JSM-6380) 46
3-3-4 多探針奈米電性量測系統 48
3-3-5 微拉曼光譜儀(Micro Raman Spectroscopy) 51
第四章 實驗結果與討論 52
4-1 鈦電極製作背閘極結構奈米碳管場效電晶體 52
4-1-1 兩端點量測 52
4-1-2 三端點量測 53
4-1-3 電崩潰實驗 55
4-2 閘極介電層厚度對奈米碳管場效電晶體效能影響 57
4-3 背閘極結構奈米碳管場效電晶體之光導現象 59
4-3-1 三端點量測 59
4-3-2 閘極偏壓對光電流之影響 61
4-3-3 汲極偏壓對光電流之影響 63
4-3-4 激發源之功率密度對光電流之影響 64
4-3-5 激發源波長對光電流之影響 67
4-4 懸空奈米碳管元件的製作 72
4-4-1 後蝕刻製程 72
4-4-2 直接於金屬電極成長單壁奈米碳管 75
4-5 懸空奈米碳管的電性及拉曼光譜分析 78
4-6 懸空奈米碳管的光導現象 81
4-6-1 三端點量測 81
4-6-2 激發源功率密度對光電流之影響 82
4-6-3 激發源波長對光電流之影響 87
第五章 總結與未來展望 91
5-1 總結 91
5-1-1 背閘極結構奈米碳管場效電晶體之光電流量測 91
5-1-2 懸空奈米碳管元件之製作 91
5-1-3 懸空奈米碳管元件電性量測 92
5-1-4 懸空奈米碳管元件光電流量測 92
5-2 未來展望 93
附錄A 背閘極元件B2光電流量測之Time-Current曲線 95
附錄B 懸空元件TS1光電流量測之Time-Current曲線 100
附錄C 懸空元件TS2光電流量測之Time-Current曲線 102
參考文獻 106

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