Label-Free Biomolecule Detection with a Dielectric-Modulated Nanocavity in High-κ MgZnO/ZnO MOS-HEMT: Influence of Structural Parameters on Biosensor Performance

This work presents an MgZnO/ZnO-based metal oxide semiconductor high-electron-mobility transistor (MOS-HEMT) biosensor that employs a dielectric-modulated nanocavity for the label-free detection of biomolecules. The sensor architecture features a nanogap cavity beneath the gate area, functioning as the active sensing site for the detection of biomolecules like uricase, ChOx, streptavidin, and proteins. The influence of critical device parameters, such as gate width (W g ) of 100 μm, gate length (L g ) of 0.3 μm, barrier layer thickness (d MgZnO ) of 15 nm, and a high- κ dielectric with an oxide thickness of 25 nm, on output characteristics and biosensor sensitivity is methodically examined. An analytical model is established to assess the two-dimensional electron gas density, drain current (I D ), transconductance (g m ), and capacitance–voltage characteristics in relation to variations in biomolecule permittivity. At a biomolecule dielectric constant of 2.5, the suggested biosensor exhibits a substantial alteration in drain current, reaching 170.65 mA, underscoring its exceptional sensitivity and swift reaction. The results validate the capability of the MgZnO/ZnO MOS-HEMT with a high- κ dielectric and nanocavity design for effective, label-free biomolecular detection in real-time sensing applications.