Effect of the Surface Modification on the Electric Properties of Poly Crystalline Silicon Nanowire Field-Effect Transistors

• Main Authors: Feng, Mei-Huei, 馮美惠
• Other Authors: Yang, Yuh-Shyong
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/47398896402071661740

碩士 === 國立交通大學 === 分子醫學與生物工程研究所 === 101 === Recent studies have been demonstrated that poly crystalline silicon nanowire field-effect transistor (poly-SiNW FET) can serve as a highly sensitive and label-free transducer for biosensing applications. Experimental result showed that the electrical characteristics of the poly-SiNW FET strongly correlate to the surface properties of the NW. Here, we demonstrate that the electrical characteristics of the poly-SiNW FETs can be modulated by the surface modification process of functional groups with various pKa values and hydrophobicity, which include amine, methyl, carboxyl and oxide. X-ray photoelectron spectroscopy (XPS) and the liquid morphology were employed to confirm and analyze the degree of the surface modification of the NW. Two polymers, poly(sodium 4-styrenesulfonate) (PSS) with negative charge and poly(allylamine hydrochloride) (PAH) with positive charge, were used to verify the surface situation of the NW. In this thesis, the sensing conditions were determined by using liquid-gating, which was found to be suitable for biodetection and pH sensing, as a gate electrode of FET configuration to tune the electrical characteristics of SiNW FETs. We found that the ion concentration in solution would be an important factor controlling the electrical properties of the NW and the effects could be minimized efficiently by adding neutral salt, sodium chloride, into the buffer solution with highly concentration (100 mM). This study should provide useful information for optimizing the performance of poly-SiNW-based biosensor for biomedical applications.