Detection of different target-DNA concentrations with highly sensitive AlGaN/GaN high electron mobility transistors

Abstract

This paper presents the successful detection of different target-DNA concentrations using AlGaN/GaN high electron mobility field effect transistors (HEMTs). The gate was bio-functionalized with two different densities of complementary DNA before application of target-DNA. Dosages of 10−16 mol/L up to the gate saturation were tested. The DNA concentration was increased by a factor of 10 each time, and the transistor transfer characteristics were measured. The threshold voltage shift and drain–source current change depend on target concentration and obey the Sips adsorption model. The AlGaN/GaN HEMTs are highly sensitive to very low target-DNA concentrations with a detection limit of 10−14mol/L. The gates with a low probe-DNA density were saturated with a lower target-DNA concentration and presented a faster hybridization equilibrium constant.