pH值為一在日常生活中時常聽見的名詞，其代表的意義為氫離子濃度的高低，pH值越低氫離子濃度越高。氫離子濃度對環境的影響力很大，故不論是在生物、化學甚至日常生活中pH值的量測都是一個很重要的課題。
氮化銦半導體材料在表面有高濃度的電子累積現象(~1013cm-2)，其電子濃度易受到外界環境的影響而變化，故極具有感測器的潛力，本研究利用超薄的氮化銦薄膜(~10nm)來充分利用氮化銦表面電子累積的特性，以離子感應場效電晶體的形式來製作氫離子濃度感測器，在pH值2到10的範圍內，有58.33mV/pH的能士特響應(Nernst response)，其值相當接近能士特方程式所預測的59.16mV/pH的理論極限。
在電流操作模式下，施予0.5V的電壓，每單位pH值改變可造成37uA的變化量，與氮化鋁鎵異質接面製成的離子場效電晶體相比，電流變化量大了一個數量級，氮化銦表面高濃度的電子累積造成了此優異的結果。
許多感測器重要的效能指標亦被探討，如反應時間、濃度偵測極限、精確度等。
最後以偵測帶負電荷奈米金粒子的方式，來初步驗證此氫離子感應場效電晶體應用於其他帶電荷粒子偵測的潛力。

pH is a familiar noun in our daily life, it represents the concentration of hydrogen ion in a solution, the lower pH value means higher hydrogen ion concentration. pH value is significantly effective in many fields, such as biology, chemistry, agriculture and so on. The measurement of pH value is an important topic.
An intrinsic surface electron accumulation layer is existed in indium nitride. The surface electron concentration is sensitive to the variation of environment. In order to bring surface electron in to full play, ultra thin InN film (~10nm) was used in this study. The pH sensor was realized by the form of Ion Sensitive Field Effect Transistor (ISFET). In the range of pH value 2 to 10, there is Nernst response 58.33mv/pH, which is very close to the theoretical value 59.16mv/pH calculated by Nernst equation.
When operated in current mode and applied voltage 0.5V, the current variation was 37uA per pH, which is one order higher than the ISFET made by AlGaN/GaN heterostructure. It’s resulted from the property of surface electron accumulation.
Many important performance factor of sensor was investigated, such as response time, detection limit, precision, etc.
Finally, by the way of negative charged Au nanoparticles detection, it shows the potential to detect other charged particles or molecules.

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