本實驗製作銅氧化物/金/氧化鋅以及金/銅氧化物/氧化鋅三元奈米複合材料，應用於化學電阻式二氧化氮氣體感測，同時也探討溫度及濕度對奈米複合材料電阻值及氣體感測響應之影響，
　　首先以黃光微影以及電子束蒸鍍技術，在矽晶圓上製作金/鈦金屬電極，寬度與間距分別為30、15 μm，而後利用低溫水熱法成長氧化鋅奈米柱於矽基板上，再藉由光還原法將銅氧化物以及金奈米粒子添加至氧化鋅奈米柱上，形成氧化鋅三元奈米材料，並作為氣體感測元件。
　　由掃描式電子顯微鏡觀察材料的表面形貌，可見氧化鋅呈現直徑約為100 nm之六角柱狀結構，並且彼此隨機交錯；金/銅氧化物/氧化鋅試片表面充滿分布均勻、直徑約為400 nm的銅氧化物顆粒，其表面具有許多微小金顆粒；而銅氧化物/金/氧化鋅試片則出現氧化鋅奈米柱表面覆蓋滿滿銅氧化物的現象。
　　我們將因氣體吸附而造成的電阻變化率稱為響應，在25 ℃、20%濕度下，銅氧化物/金/氧化鋅電阻值則約為32.4 kΩ，通100 ppb NO2¬後的電阻值上升為73.5 kΩ，響應為127%。金/銅氧化物/氧化鋅電阻值則約為19.5 kΩ，通100 ppb NO2¬後的電阻值為33.1 kΩ，響應為70%。因銅氧化物/金/氧化鋅之氣體感測響應較高，因此我們針對銅氧化物/金/氧化鋅試片做了溫濕度效應分析。
　　我們分別在環境溫度25 ℃、35 ℃下進行不同濕度的電阻值測量，在環境溫度25 ℃下，試片在20%濕度時之電阻值為29.4 kΩ，80%濕度時之電阻值為57.9 kΩ，差異率為97%；在環境溫度35 ℃下，試片在20%濕度時之電阻值為22.5 kΩ，80%濕度時之電阻值為35.7 kΩ，差異率為76%。
　　在不同溫濕度下，進行100 ppb NO2¬氣體感測，在環境溫度25 ℃下，濕度20%時之響應為127%，持續上升至濕度65%時達最大響應274%，濕度80%時響應則下降為118%；在環境溫度35 ℃下，試片濕度20%時之響應為23%，持續上升至濕度80%時之響應93%。
　　總而言之，我們製作了銅氧化物/金/氧化鋅及金/銅氧化物/氧化鋅三元奈米複合材料，並應用於化學電阻式二氧化氮氣體感測。銅氧化物/金/氧化鋅奈米複合材料具有較高的氣體感測響應，在環境溫度25 ℃下，對100 ppb NO2的響應，濕度20%時為127%，濕度65%時為274%，而濕度80%時為118%。也發現試片電阻隨著濕度上升而增加，在25 ℃及35 ℃下之電阻差異率分別為97%及76%。

　　In this work, we produced ternary nanocomposites comprising of copper oxide/gold/zinc oxide and gold/copper oxide/zinc oxide for chemiresistive NO2 gas sensing under ambient environment. The effects of environmental temperature and humidity on the resistance and gas sensing performance were also investigated.
　　ZnO nanorods (NRs) were first grown by a low-temperature hydrothermal method on a Si substrate with pre-patterned Au/Ti electrodes prepared by photolithography. The length and width of an electrode pair were 30 and 15 μm, respectively. CuxO and Au nanoparticles (NPs) were then added in alternate orders to ZnO NRs by a photoreduction method, thus forming ternary nanocomposites.
　　The morphologies of the ternary nanocomposites were characterized by scanning electron microscopy. The ZnO NRs had a hexagonal shape with a diameter of around 100 nm. The Au/CuxO/ZnO nanocomposite showed many CuxO NPs with a size of around 400 nm. Au NPs were found mainly on CuxO NPs with uniform distribution. On the other hand, the CuxO/Au/ZnO nanocomposite showed the coverage of CuxO NPs on ZnO NRs with Au NPs in between.
　　The sensing response was calculated by measuring the ratio of resistance increase caused by gas adsorption. At 25 ℃ and 20% relative humidity (RH), the resistance of CuxO/Au/ZnO was 32.4 kΩ and increased to 73.5 kΩ after 100 ppb NO2 injection, giving a response of 127%. The resistance of Au/CuxO/ZnO was 19.5 kΩ and increased to 33.1 kΩ after 100 ppb NO2 injection, giving a response of 70%. Since the response of CuxO/Au/ZnO was higher, we analyzed the temperature and humidity effects for the CuxO/Au/ZnO sample.
　　The CuxO/Au/ZnO resistance was measured at 25 and 35 ℃ under varying RH. At 25 ℃, the resistances were 29.4 kΩ at 20% RH and 57.9 kΩ at 80% RH, giving a variation of 97%. At 35 ℃, the resistances were 22.5 kΩ at 20% RH and 35.7 kΩ at 80% RH, giving a variation of 76%.
　　We conducted 100 ppb NO2 gas sensing for the CuxO/Au/ZnO sample at 25 and 35 ℃ under varying RH. At 25 ℃, the response started with a value of 127% at 20% RH, increased till 65% RH with a maximum response of 274%, and decreased to 118% at 80% RH. At 35 ℃, the response started with a value of 23% and increased monotonically to 93% at 80% RH.
　　In conclusion, we produced CuxO/Au/ZnO and Au/CuxO/ZnO ternary nanocomposites for chemiresistive NO2 gas sensing. The CuxO/Au/ZnO nanocomposite showed better performance with a response of 127% at 20% RH, 274% at 65% RH, and 118% at 80% RH at 25 ℃ upon exposure to 100 ppb NO2. It was also found that the resistance increased as the humidity increased with variations of 97% and 76% at 25 and 35 ℃, respectively.

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