由於重金屬鉛無法被人體代謝，所以攝入的鉛離子將會逐漸堆積在體內並影響人體的神經系統。而人體內累積的鉛離子大多數來自飲用水、自來水和食物中的水，使得鉛在水中的濃度一直是人們所重視的議題。然而市面上對於鉛離子感測的技術雖然行之有年，卻難有可以兼顧靈敏度以及使用方便性的感測器出現：傳統實驗室儀器能夠達到極低的偵測極限，其操作卻極為複雜且量測非常耗時；相對地，雖然離子選擇性電極能夠更為簡便快速，卻無法量測低濃度的離子。為了能幫助助人們能以簡便的方式快速監測日常生活中的飲用水中的鉛離子濃度，本研究著重在研發一種可擁有簡便操作方式又可以靈敏的感測鉛離子的新式感測器。本實驗結合了鉛離子選擇性有機薄膜與高靈敏度、高化學抵抗力的AlGaN/GaN的HEMT晶片，在導入了界面電雙層結構，並以極短間距的外加閘極施以大電場，使得此鉛離子感測器能擁有超越傳統能斯特元件的高靈敏度與極低的偵測極限。在台灣，政府規範自來水中鉛離子濃度需小於50 ppb，換算後為2.42×10-7 M。而在本實驗結果中此新式感測器對於鉛離子的感應濃度範圍為10-10 M到10-5 M。此結果不僅廣泛涵蓋了政府對於鉛離子濃度的限制，更是得到能夠比擬傳統實驗室大型機台的極低感測極限。

Lead is an extremely hazardous heavy metal. Since it is impossible for liver to metabolize or decompose heavy metals, accumulation of lead in human body causes damage to human nervous system gradually. Thus, the detection of lead ion levels in drinking water, tap water and other liquid coming from food, the easiest way for the ingestion of lead, becomes necessary. However, the traditional laboratory methods are really complex and time consuming, and require bulky and costly machinery. On the other hand, although the electrochemical ion selective electrode can be used easily, the poor stability and high detection limit of this kind of sensor is still a big problem. In this research, a small size, highly sensitive, short response time, easy to fabricate and convenient lead ion selective high electron mobility transistor (ISHEMT) has been investigated. This new type of Pb sensor aims to make end-user easily operate in drinking water for rapid measurement. By combining ion-selective membrane with AlGaN/GaN HEMT and introducing electric double layer (EDL) structure with extremely small gap distance for external gate, a transducer with higher sensitivity than Nernst behavior can be achieved. Taiwan government suggest lead containing in tap water should be less than 50 ppb, equaling to 2.42×10-7 M. In this experiment, the dynamic range of the Pb ISHEMT sensor is from 10-10 M to 10-5 M. This result cannot only cover the objective widely, but also be comparable to the detection limit of laboratory machine, i.e. ICP-MS.

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