A Biosensor Based on GaN Field Effect Transistor

Siddharth Alur1, Tony Gnanaprakasa2, Hui Xu1, Yaqi Wang1, Aleksandr L. Simonian2, Omar A. Oyarzabal3, and Minseo Park1*

1Department of Physics, 2Materials Research and Education Center, Department of Mechanical Engineering, and 3Department of Poultry Science, Auburn University, Auburn, Alabama 36849 *corresponding author

Keywords: High electron mobility transistor, DNA, Biosensor

Abstract

Among the various techniques of biosensing, field effect transistor (FET) based detection of biological materials is interesting due to its label-free detection and rapid identification. Recently, GaN has been considered as a promising candidate for biosensor application due to its inertness to a chemical environment. In this work, AlGaN/GaN high electron mobility transistor (HEMT) wafer with a 2DEG mobility of 1300 cm2/v-s and a sheet carrier density of 1×1013 cm-2 was used as a sensor platform. Ti/Al/Ni/Au was used as source and drain contacts and a Ni/Au contact were deposited for the gate electrode. Polydimethylsiloxane (PDMS) was used as an encapsulating agent. The DNA immobilization on the Au gate was carried out using thiol-based chemistry. Our preliminary results suggest that it is possible to detect DNA using AlGaN/GaN HEMT sensor. However, further experiments will 1) assess if mismatched target DNA contribute to any change in current measured, and 2) evaluate the reproducibility and the accuracy of the device.

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