在本論文中，吾人研製一系列氮化鋁鎵蕭特基二極體式氫氣感測器元件，並在感測區域加入奈米結構，主要重點在於奈米尺寸（＜ 100 nm）之材料具有較大之比表面積，利用旋轉塗佈的方式將二氧化矽奈米粒子（SiO2 nanoparticles）及聚苯乙烯奈米球（Polystyrene nanospheres）分散於基材表面並以不同的製程方式，製作出不同的表面形態結構，可大幅提升元件的感測特性；本文所提出的元件是在空氣環境下通入不同濃度的氫氣來研究其氫氣感測及響應特性。
首先，吾人製作並研究一個未加入奈米結構之鈀金屬／氮化鋁鎵半導體的蕭特基二極體氫氣感測器，由於氮化鋁鎵材料具有寬能隙以及良好的熱穩定度特性，相較於傳統之半導體所研製的氣體感測器，本文所提出之金屬／半導體式的氫氣感測器可操作在寬廣的溫度範圍，並且擁有良好的感測靈敏度以及蕭特基能障變化。
接著，吾人在元件上塗佈單層聚苯乙烯奈米球，利用聚苯乙烯溶於丁酮的特性，將覆蓋在聚苯乙烯奈米球上之鈀金屬以舉離的方式去除，使得蕭特基金屬表面形成金字塔狀的鈀奈米結構。利用此奈米結構可大幅提升元件特性。另外一方面，吾人製作並研製一系列塗佈不同濃度二氧化矽奈米粒子的元件，經由實驗結果得知，插入二氧化矽奈米粒子在鈀金屬以及氮化鋁鎵之間，以形成鈀／二氧化矽／氮化鋁鎵（金屬／氧化物／半導體）的氫氣感測器，可以大幅降低空氣中的穩態電流，並且藉由二氧化矽奈米粒子較大的比表面積，提供較多的氣體吸附座，以大幅提升元件的感測特性。並且，針對各元件之表面吾人予以不同的儀器分析，進一步證實經過奈米球(奈米粒子)處理的鈀金屬表面，較未處理的鈀金屬表面的粗糙度與比表面積明顯提升。儀器包括掃描式電子顯微鏡及原子力顯微鏡。
最後，吾人製作並研製一個由氧化鋅奈米粒子當作電流通道的半導體式二氧化氮感測器。藉由氧化鋅奈米粒子較大的比表面積，提供較多的氣體吸附座，以大幅提升元件的感測特性。並且，吾人探討經過鍛燒處理的元件，對於感測特性的影響。

In this work, we present a series of AlGaN-based Schottky diode hydrogen-sensing devices. The nanospheres (nanoparticles) are used to make different nanostructure on the surface of sensing area. The key point is that the nanoscale (< 100 nm) material provides a large specific surface area. Different nanostructures were fabricated by effectively coating the PS nanospheres (NS) and SiO2 nanoparticles (NPs). The structures were used to enhance the sensing performance. The hydrogen sensing and response characteristics of studied devices under different hydrogen concentrations are investigated in an air atmosphere.
Firstly, a Pd/AlGaN (M-S) Schottky diode hydrogen sensor is fabricated and investigated. Due to wide bandgap and superior thermal stability, the studied AlGaN-based diode-type hydrogen sensor exhibits a higher detection sensitivity, a larger Schottky barrier height variations, and a wide temperature range.
Secondly, the pyramid-like Pd structure on the Pd metal surface is fabricated by coating a monolayer PS NS, etching PS NS by butanone, and lifting-off the PS NS, which is covered by Pd metal. The studied device with the pyramid-like Pd structure can significantly enhance the sensing performance. On the other hand, a series of devices with an insertion layer of SiO2-NPs are fabricated and investigated. According to the experimental results, Pd/SiO2 NPs/AlGaN-based (metal/oxide/semiconductor) hydrogen sensor is fabricated by inserting SiO2-NPs layer between Pd/AlGaN interface. The structure can significantly reduce the baseline current in air and service more gas adsorption sites to enhance the sensing performance.
Third, the analyses are applied to examine the surfaces morphology with and without nanostructure, including scanning electron microscope (SEM) and atomic force microscopic (AFM) instrument. It further confirms the surface roughness and specific surface area of the device with nanostructure is obviously upgraded.
Finally, ZnO NPs-based NO2 gas sensors are investigated. The ZnO NPs have a larger specific surface area and can offer more gas-adsorption sites to significantly enhance sensing performance. And the studied device with calcination treatment is carried out to investigate the effect on sensing characteristic.

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