Nanoscale devices have enabled AlGaN/GaN MOSHEMTs to serve as highly sensitive platforms for the detection of biomolecules, including proteins, enzymes, DNA, and cells, due to their superior electrical properties. These devices support rapid and precise biosensing, enhancing consumer access to healthcare applications such as blood glucose monitoring. FET-based biosensors, fabricated using CMOS technology, offer advantages such as high sensitivity, compact size, reduced response time, and cost-effectiveness. Conventional silicon-based FETs, however, face limitations under harsh conditions, including high temperatures and aqueous environments, and require extensive sample pre-treatment. GaN-based HEMTs overcome these constraints with high transconductance, low noise, and the formation of a two-dimensional electron gas (2DEG) near the surface, which significantly improves sensitivity to biomolecule adsorption. The electric field distribution and energy band profile of the AlGaN/GaN MOSHEMT are altered by the addition of an InGaN notch, which improves gate control, lowers short-channel effects, increases threshold voltage stability, and improves subthreshold properties. Strong polarization effects in III-nitride materials, where the InGaN layer integrates extra polarization charges that optimize carrier confinement and modulation efficiency, are the main cause of these advances. Dielectric modulation in the gate oxide layer creates a nanogap that can be filled with biomolecules, directly affecting the surface charge and altering device parameters. TCAD simulations were employed to evaluate the proposed MOSHEMT design, using neutral biomolecules such as Bacteriophage T7, Gelatin, APTES, Glucose, and Urease, and charged biomolecules with varying charge densities. Changes in threshold voltage and drain current were used as key sensing metrics to detect biomolecule presence. The study demonstrates that dielectric modulation, along with optimized device geometry and material selection, provides an effective and reliable approach for biosensing applications. These findings highlight the potential of AlGaN/GaN MOSHEMTs for next-generation biomolecule detection with high sensitivity and fast response.
Mishra et al. (Wed,) studied this question.