| Summary: | 碩士 === 國立清華大學 === 電子工程研究所 === 98 === Ultrathin (~10 nm) InN ion sensitive field effect transistors (ISFETs) modified with 3-aminopropyltrimethoxysilane (APTMS) by molecular vapor deposition (MVD). It is used to selectively detect calcium ions. The ultrathin InN ISFETs have high sensitivity and short response time for anion detection, showing a great potential for chemical and biological sensing applications. The change of water contact angle on InN surface was observed from 74o, indicating the O2 plasma cleaning, to 61o after 1 hour vapor deposition. APTMS with –NH2 terminal functional groups react to the cross-linker, glutaraldehyde, is used to immobilize O-phospho-l-tyrosine (p-Tyr) with phosphate end. After immersed in 1 mM p-Tyr solution for 12 hours, the functionalized InN ISFET is used to complex with calcium ion. A source-drain current increase is observed when calcium ion introduced to the gate region of ISFETs. The current increase is attributed to the binding of positively charged calcium ion. The sensitivity is about 1.11 %/decade, and detection limit is 10-6 M. When InN ISFET is immersed to sodium chloride, potassium chloride, magnesium chloride solution individually, we can calculate that the sensitivity on calcium ion is 6.53, 3.2, 27.9 times than sodium, potassium, and magnesium ions.
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