Design and modeling of resonant tunneling transport-controlled voltage-induced double quantum dot channel nanowire field-effect-transistor (DQD-FET) for multi-threshold current levels

The article deals with the modeling of gate voltage controlled resonant tunneling transport in a complementary-metal–oxide–semiconductor (CMOS) compatible double quantum dot channel nanowire field-effect-transistor (FET). Appropriate applied voltages at two separate gates, gate-1 and gate-2 of the device form two voltage-tunable quantum dots underneath the gates, within the nanowire channel. The quantum dot eigenstates are tuned by varying the applied gate voltages to enable voltage-modulated resonant tunneling transport. Such transport is modeled by employing a Schrödinger-Poisson self-consistent framework using non-equilibrium Green’s function (NEGF) formalism. Electron–phonon scattering within the nanowire channel is also considered. The transfer characteristics exhibit multiple current thresholds in the range of 10⁻⁴ μA/μm–1 μA/μm due to resonant tunneling. The phonon scattering is observed to significantly depend on nanowire geometry and applied gate voltages, with tunneling dominated quasi-ballistic transport occurring at higher gate voltages. Also, steep sub-threshold slopes of 30 mV/decade–8 mV/decade range and transconductance in the range of 10⁻⁷ μS/μm–1 μS/μm at room temperature are obtained by varying the nanowire diameter in the range of 20 nm–5 nm. Therefore, such device architecture exhibits significant potential for achieving multi-current thresholds in a CMOS compatible architecture at room temperature.