本研究係以氨基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)之感測器。實驗中，首先製作金/磷化銦鎵蕭特基二極體，再以溶液含浸法將氨基硫醇單分子層修飾於金膜表面，並以此元件進行氮氧化物感測特性之探討。
文中改變氨基硫醇含浸溶液之濃度來選擇最適之元件製備條件，此外也針對了不同碳數及分子結構之氨基硫醇來探討。為了測定不同氨基硫醇在金膜上之吸附量，本實驗以循環伏安法來加以分析；在元件感測實驗方面則改變NOx濃度、溫度、濕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。
由實驗結果可知，在金膜上之吸附量隨著濃度的增加亦增加，但當氨基硫醇濃度達到1mM時其吸附量趨於飽和；不同碳數及分子結構的氨基硫醇單分子層，則出現高碳數之氨基辛烷硫醇吸附量比氨基己烷硫醇更多的結果，而內含苯環結構的氨基苯酚之吸附量則最少。此結果與其製備成元件後對NOx感測靈敏度呈現相同趨勢；在25℃，100 ppm下，氨基辛烷硫醇元件對NO2之感測靈敏度為44.19，響應時間為236秒，回復時間為7541秒；NO之感測靈敏度為8.43，響應時間為1039秒，回復時間為2635s ; 氨基己烷硫醇元件對NO2之感測靈敏度為38.63，響應時間為187秒，回復時間為1004秒；NO之感測靈敏度為2.80，響應時間為217秒，回復時間為368秒。
以氨基硫醇修飾Au/InGaP元件進行感測氣體濃度之探討時，發現元件對NOx之感測靈敏度隨濃度增加而增大;另一方面對於感測環境的操作變因進行探討，以氨基硫醇修飾Au/InGaP元件進行感測，發現感測靈敏度隨溫度之升高而降低，即在25℃下為最佳之感測溫度;而對於環境濕度而言，感測靈敏度在相對濕度高於50%之後會顯著的下降，即元件適合在環境相對濕度50%以下操作。此外以甲醇、乙醇、一氧化碳、二氧化碳、甲醛、甲烷、氫氣、氨氣、丙酮等常見工業用危害性氣體來進行選擇性之探討，發現元件對氮氧化物呈現極佳之選擇性。
為了探究氣體感測的機制，在感測不同濃度二氧化氮氣體時，個別就修飾癸二硫醇以及氨基辛烷硫醇之元件，進行蕭特基能障下降量之計算，由計算結果可知，氨基辛烷硫醇(AOT)感測100 ppm二氧化氮時，蕭特基能障的下降量為0.09868 V，癸二硫醇(DDT)元件則為0.07386 V。在感測二氧化氮氣體時，氨基硫醇元件會比雙硫醇元件具有更大的蕭特基能障下降量。
此外以Langmuir吸附來描述元件對NO2之穩態感測行為，感測靈敏度與濃度之關係符合Langmuir模式。對於氨基辛烷硫醇(AOT)元件，反應階數為0.5階，平衡常數(K)為4.15×10-1；對於癸二硫醇(DDT)硫醇元件，反應階數為1階，平衡常數(K)為4.21 ×10-2。進一步以吸附動力模式來描述元件對NO2之暫態感測行為。以穩態模式求得之反應階數代入，對於氨基辛烷硫醇元件，正向反應速率(k1)為4.25×10-3；對於癸二硫醇元件，正向反應速率(k1)為4.293×10-4。

In this work, we devoted to fabricate the amino-alkane thiol monolayer decorated Au/InGaP Schottky diode NOx gas sensor. Experimentally, we prepared Au/InGaP Schottky diode and deposited the amino-alkane thiol self-assembled monolayer (SAM) on Au film of device sequentially using immersion method. The effect of different solution concentrations for immersion (=0.01, 0.05, 0.1, 0.5, 1, 2 mM), carbon numbers and structures of alkyl chain have been comprehensively discussed in our research. Cyclic voltammetry is applied to simulate the amino-alkanethiol monolayer self-assembled on Au surface and its adsorption amounts is further calculated by reduction peak current analysis. In addition, the sensing performance of the amino-alkanethiol modified Au/InGaP Schottky diode under different NOx concentrations, temperatures, humidities has been researched. The reduction of Schottky barrier height is calculated as well as the thermodynamic and kinetic analysis at the end of the study. Langmuir model is successfully fitted for thermodynamic analysis and then forward reaction rate constant is derived from kinetic analysis.

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