A strain-aware electromechanical framework for III-nitride axial nanowire heterostructures toward an energy-efficient high-frequency tunnel FET

A polarization-engineered III-nitride nanowire tunnel field-effect transistor (TFET) is investigated for low-energy, high-frequency operation under strain relaxation. Unlike approaches that optimize polarization-assisted tunneling primarily from an electrical perspective, the proposed framework introduces mechanical strain retention and critical structural dimensions as explicit constraints before electrical optimization. A coupled Wentzel–Kramers–Brillouin tunneling analysis and finite-element electromechanical framework evaluates multiple heterostructures in terms of critical thickness, strain relaxation, polarization degradation, and tunneling strength. The InN/In \(_{0.65}\) Ga \(_{0.35}\) N/InN axial nanowire is identified as a balanced structure with strong tunneling under both coherent and relaxed strain conditions. Device simulations show steep switching with a subthreshold swing of 11.3 mV/dec at 300 K, suppressed leakage, and transconductance of 723–997 \(\upmu \) S over 225–400 K. Femtofarad-scale gate capacitance enables cutoff frequencies of 268–76 GHz, indicating potential for millimeter-wave operation. Zero-bias rectification is enabled by polarization-induced built-in electric fields, which enhance band-to-band tunneling without an externally applied DC bias. The device exhibits high intrinsic gain, low noise, and high power gain across the Ka-, V-, and early W-band ranges. System-level operation is validated using a non-quasi-static compact model for a differential power detector with high-responsivity drain-biased detection and polarization-driven zero-bias rectification, demonstrating strain-aware polarization control for strain-tolerant millimeter-wave TFET operation.