Device optimization and sensitivity analysis of a double-cavity graded MgZnO/ZnO MOSHEMT for biomolecule detection

Abstract

The detailed analytical model of biosensing parameters was proposed for a double-cavity graded MgZnO/ZnO metal oxide semiconductor high electron mobility transistor (MOSHEMT) with cap layer-based biosensor including transfer characteristic, output characteristic, change in cut-off voltage ( ΔVoff ), transconductance ( gm ), sensitivity, and selectivity. A thorough investigation of dielectric modulation in a double nanogap cavity under the gate was conducted with a focus on improving the sensing characteristics of a MOSHEMT to indicate the presence of biomolecules like Uricase, Streptavidin, Protein, and ChOx. The dielectric modulation and the Poisson equation were used to determine the effective capacitance and cut-off voltage in the cavity region. Consequently, the changes in the cut-off voltage and the drain current of the device were used as the sensing metrics for the detection of biomolecules in the cavity regions. It was found that the proposed graded MgZnO/ZnO MOSHEMT-based biosensor demonstrates a higher change in cut-off voltage and drain current in comparison to the previous works, suggesting higher sensitivity for biomolecules.