本研究係以雙硫醇單分子層修飾金/磷化銦鎵(Au/InGaP)蕭特基二極體作為氮氧化物(NOX)之氣體感測器。實驗中，首先製作金/磷化銦鎵蕭特基二極體，再以含浸法將雙硫醇單分子層(簡稱SAM)修飾於金膜表面，並以此元件進行氮氧化物感測特性之探討。
文中改變雙硫醇碳數及含浸時間來選擇最適之SAM製備條件；另外，改變NOx濃度、溫度及氣體種類等操作變因來探討元件對NOx感測特性，如:靈敏度、選擇性、響應及回復速率等性質之影響。為測定雙硫醇分子在金膜上之吸附量，以循環伏安法來加以分析。
由實驗結果可知，當雙硫醇之碳數3~10間時，雙硫醇分子在金膜上之吸附量亦增加，故元件對NOx感測靈敏度亦隨之增加；但當碳數大於10時，雙硫醇在金膜上之吸附量反而減少，導致元件對NOx之感測靈敏度亦隨之下降。換言之，癸二硫醇(碳數10)為最佳之修飾劑。另外，由含浸時間探討顯示，當含浸時間增加時，SAM量增加，所得元件之感測靈敏度亦隨之增加，當含浸時間為60小時，元件呈現最佳之感測特性，在30℃，100 ppm下，元件對NO2之感測靈敏度為19.9，響應時間為10.7s，回復時間為27.0s；NO之感測靈敏度為8.7，響應時間為16.9s，回復時間為43.1s。
以癸二硫醇修飾Au/InGaP元件進行操作變因之探討時，發現元件對NOx之感測靈敏度隨濃度增加而增大，但隨溫度之升高而降低，即在30℃為最佳之感測溫度。以乙醇、二氧化碳、一氧化碳、甲醇、甲醛、氫氣、氨氣等氣體來進行選擇性之探討，發現元件對一氧化碳、甲醇、甲醛、氫氣、氨氣無響應，而對乙醇、二氧化碳呈現極佳之選擇性。進一步以吸附動力模式來描述元件對NOx之感測行為。結果發現暫態感測動力符合一階吸附模式，且在穩態下，感測靈敏度與濃度之關係符合Langmuir模式。

In this work, we devoted to fabricate the NOx sensor based on Au/InGaP Schottky diode. In order to enhance NOx selectivity and sensing response, self-assembled monolayer (SAM) – dithiol was used for modifying the Schottky contact because of its self-assembled property and particular functional group. The effect of SAM immersion time (t=1,6,12,24,36,48,60h) and carbon number of SAM (n=3,6,9,10,11,16) has been comprehensively discussed in our research. In addition, the selectivity and sensing performance of dithiol modified Au/InGaP Schottky diode in different temperature and NOx concentration has been researched. With a view to fabricating the best NOx sensing performance Schottky diode, cyclic voltammetry is applied to simulate the thiol monolayer self-assembled on Au surface and its amount is also further calculated by reduction peak current analysis. At the end of this study, the first order kinetic and thermodynamic model has been fitting successfully with NOx sensing results.

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