本實驗旨在探討氧化銦一維奈米結構之成長及其性質。首先，我們藉由加熱式管狀爐，以化學氣相沉積法(Chemical Vapor Deposition，CVD)的方式，並透過不同成長參數的調變，成功地合成一系列不同形貌的氧化銦(In2O3)奈米線。在掃瞄式電子顯微鏡(SEM)的觀測下，我們發現奈米線的線徑隨成長溫度的上升而降低，但線長隨著溫度的上升而增加，因此在成長溫度950℃時，我們得到一外觀比最大的奈米線，分別是線徑100nm及線長20µm；接著對此奈米線進行X 射線能量散佈分析儀(EDX)的分析，可證明此奈米線的氧及銦的合成成份是正確的比例。藉由X射線繞射分析儀(XRD)的分析，我們得到此奈米結構為立方晶相的氧化銦。
在分析完基本的形貌與材料結構後，我們將對其進行氣體感測的研究。我們分別討論了奈米線線徑、感測溫度及不同感測氣體對氣體感測元件的影響。在同樣的量測參數下，我們發現元件的感測響應隨著奈米線線徑降低而大幅提升，以線徑100nm的奈米線有著最佳響應。另外，此實驗製備出的感測元件有極廣的操作溫度範圍，在25℃~300℃下都可正常地作用，而在300℃時此元件有最好的響應。最後，針對不同感測氣體的部分，我們發現此實驗中的感測元件對甲醇、乙醇及酒精都有不錯的響應，但實驗結果顯示，此元件對酒精有較高的選擇性。
我們針對兩種不同形貌的奈米線做場發射(Field Emission)的電性研究，以成長完成的奈米線及奈米塔試片做量測後，可以發現氧化銦奈米線擁有起始電場為3.4 V/µm的良好場發射響應；但另一種氧化銦奈米塔，由於其特殊形貌的影響，其具備起始電場為2.5 V/µm的更佳響應。這兩種形貌的奈米線都擁有很高的場發射增強因子(β)分別是奈米塔為3590而奈米線為2123，可推斷In2O3材料有不錯的場發性質，有應用於電子元件的潛力。

In this study, we have successfully synthesized Indium Oxide nanowires through Vapor-Liquid-Solid method by using conventional furnace system. We found that if the growth temperature increases, the radius of nanowires would decrease from 500nm to 100nm with the length increasing from 5µm to 20µm. Moreover, we changed the positions of the substrates, and founded that if we put the substrate reversely, the nanotowers would be synthesized. Subsequently, these two kinds of nanostructures were analyzed by EDX and XRD. The measured result shows that nanowires and nanotowers synthesized in our study are Indium Oxide and cubic structure.
In the application section, we first discussed the impact causing by different sizes of nanowires. We can obtain that the device fabricated by the narrowest nanowires of 100nm has the better sensitivity than others. Then, we investigated the gas sensor device working at different temperatures and founded that it had the highest sensitivity at working temperature of 300℃. Finally, we use different kinds of gas including methanol, ethanol and acetone as target gas, and demonstrated that the device in our paper had good selectivity toward ethanol.
Another application is Field Emission device. Nanowire has the turn-on field of 3.4 V/µm, and nanotower has the turn-on field of 2.5 V/µm. Both of them have higher β value that are 3590 for the nanotowers and 2123 for the nanowires . So, we can demonstrate that gas sensors or electrical devices based in nanowires in this study have excellent performance.

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