Electrical detection of deoxyribonucleic acid hybridization with AlGaN∕GaN high electron mobility transistors

Au-gated AlGaN∕GaN high electron mobility transistor (HEMT) structures were functionalized in the gate region with label-free 3′-thiol-modified oligonucleotides. This serves as a binding layer to the AlGaN surface for hybridization of matched target deoxyribonucleic acid (DNA). X-ray photoelectron spectroscopy shows the immobilization of thiol-modified DNA covalently bonded with gold on the gated region. Hybridization between probe DNA and matched or mismatched target DNA on the Au-gated HEMT was detected by electrical measurements. The HEMT drain-source current showed a clear decrease of 115μA as this matched target DNA was introduced to the probe DNA on the surface, showing the promise of the DNA sequence detection approach for biological sensing.