本論文旨在利用水熱法(hydrothermal growth, HTG)進行氧化鎳(nickel oxide, NiO)奈米片(nanosheets, NSs)之成長並結合延伸式閘極場效電晶體之結構(Extended-Gate Field-Effect Transistor, EGFET)以應用於pH感測之研究，藉由NiO奈米片具備大表面積以利吸附溶液中之酸鹼離子之特質，增進元件之pH感測靈敏度。
本論文之研究工作概分為三部分，第一部分為利用水熱法製備出NiO奈米片，並藉由調變水熱製程參數觀察其外觀形貌之變化。最後透過掃描式電子顯微鏡(SEM)、能量色散X-射線光譜(X-ray energy dispersive spectroscopy, EDS)及X-光繞射(x-ray diffraction, XRD)等材料分析探討水熱製程參數及退火溫度之調變對於NiO奈米片之影響；第二部分為延伸式閘極之製備及pH量測系統之設置。結合於鈦/金(Ti/Au)導電基板上水熱法成長之NiO奈米片與EGFET之封裝製程，製備pH感測元件。pH量測系統使用Keithley 2636A作為量測機台，n-MOSFET為市售已封裝之CD4007UB，參考電極為Ag/AgCl，在量測過程中固定溫度為300 K，NiO奈米片感測面積為0.5×0.5 cm2，延伸式閘極與參考電極距離固定為2 cm；第三部分為以NiO奈米片pH感測元件進行pH量測。首先將針對感測膜表面形貌與元件製程退火溫度進行探討並觀察元件感測特性之變化。於感測膜表面形貌方面，實驗結果顯示，以水熱法製備之NiO奈米片感測特性優於濺鍍沉積製備之NiO薄膜，其中以水熱成長9小時、奈米片典型長度與厚度分別為1.5-2 "μ" m與10-40 nm之元件表現最佳。於元件製程退火溫度方面，發現以退火溫度為400℃時，具有最佳之感測特性，靈敏度為54.71 mV/pH，線性度為0.996。續以此最佳化之元件進行遲滯效應與時漂效應之探討，實驗結果顯示元件於緩衝溶液pH 7-4-7-10-7循環中之遲滯電壓為7.01 mV，於緩衝溶液pH 7中量測時漂值為0.71 mV/h，說明元件具有量測之重複性及長時間量測之穩定性。
本論文以水熱法成長NiO奈米片所製備pH感測元件，於製備上具製程簡易、製作成本低廉及大面積製作等優點，極具規模化生產潛力；於感測性能上，其奈米片表面形貌證實可有效增進感測特性，預期對於未來pH元件之開發應用將可提供助益。

Sensing electrodes based on the hydrothermal growth (HTG) of NiO nanosheets (NSs) are fabricated and their pH sensing performance in 2-12 pH buffer solutions using an extended-gate field-effect transistor (EGFET) configuration is demonstrated. Effect of surface-to-volume (SV) ratio of the prepared NiO NSs which is related to HTG parameters on sensing reponse is investigated. The sensing electrode based on NiO NSs HTG for 9 h-sample shows a high response of 54.71 mV/pH, a good linearity of 0.996, and low hysteresis voltage of 7.01 mV, which could be mainly attributed to the improved SV ratio of the NSs structure.

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