Affiliation:
1. School of Nano-Tech and Nano-Bionics University of Science and Technology of China Hefei 230026 China
2. Key Laboratory of Multifunctional Nanomaterials and Smart Systems Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of Sciences Suzhou 215125 China
3. The College of Materials Science and Engineering Shanghai University Shanghai 200072 People's Republic of China
4. School of Electrical and Mechanical Engineering Changchun University of Science and Technology Changchun 130022 China
Abstract
AbstractAlGaN/GaN high electron mobility transistors (HEMTs) have been widely studied in the field of bio‐sensing due to their advantages such as high sensitivity, excellent biocompatibility, rapid response and corrosion resistance. Previously, attention was focused on the impact of width/length ratio (W/LSD) on transconductance (gm) to improve the sensitivity, however, the position of gate (LGS/LGD) also affects the sensitivity of HEMT sensors towards biosensing. Herein, we optimized the gate geometry based on the fixed gate position at LGS/LGD=3/5. Through theoretical analysis, design, and fabrication, three AlGaN/GaN HEMT devices with W/LSD ratios of 800 μm/200 μm, 800 μm/100 μm, and 800 μm/50 μm were developed, consistently maintaining LGS/LGD at 3/5 and LG/LSD at 1/5. Using cortisol as the biochemical detection target, the sensitivity, specificity, and linearity of three different gate structures of AlGaN/GaN HEMT biosensors were validated. The results indicated that with the increase of W/LSD and the decrease of LG, the sensitivity of the three AlGaN/GaN HEMT devices significantly improved, reaching 0.455 μA dec−1, 0.880 μA dec−1, and 2.316 μA dec−1, respectively. The device with W/LSD=800 μm/50 μm and LG=10 μm showed a sensitivity approximately 5 times that of the device with W/LSD=800 μm/200 μm and LG=40 μm, and about 2.6 times that of the device with W/LSD=800 μm/100 μm and LG=20 μm, thereby validating the correctness of the theoretical calculations. Moreover, the fabricated HEMT devices were capable of detecting cortisol concentrations ranging from 10 fM to 100 μM in 1×PBS, demonstrating specificity to cortisol and good linearity, with R2 values of 0.98456, 0.98038, and 0.99232, respectively. The detection results verified the outcomes of theoretical analysis. This paper systematically investigates the integration of theoretical analysis with the practical application of AlGaN/GaN HEMT devices, providing a new method to enhance sensitivity in biochemical detection using HEMT devices.