Highly sensitive extended gate-AlGaN/GaN high electron mobility transistor for bioassay applications

Abstract

Herein, an extended gate-AlGaN/GaN high electron mobility transistor (EG-AlGaN/GaN HEMT) with a high sensitivity for bioassay has been developed. The major difference between the EG-AlGaN/GaN HEMT transducer and a traditional AlGaN/GaN HEMT transducer is the sensing region. By extending the gate electrode and separating the sensing region from the channel of the AlGaN/GaN HEMT, our EG-AlGaN/GaN HEMT has a much larger sensing area and therefore achieves a low limit of detection (0.1 pg mL⁻¹). Additionally, our transducer exhibits excellent linearity (R² = 0.9934) with a wide range (from 0.1 pg mL⁻¹ to 100 ng mL⁻¹). We also demonstrate that the larger area of the extended sensing region can provide a larger current response of the transducer. The results give a proof-of-concept demonstration of the utilization of the EG-AlGaN/GaN HEMT for trace-level biological detection.