A THz-range planar NDR device utilizing ballistic electron acceleration in GaN

A planar and ultra-short gallium nitride (GaN) diode structure is investigated as a potential Terahertz (THz) range negative differential resistance (NDR) diode. An empirical velocity-field relation, exhibiting a peak electron velocity as high as 7 × 107 cm/s, is employed to characterize the high-field transport in the simulations, accounting for ballistic electron acceleration and velocity reduction due to phonon build up. The resulting device operation is in accumulation-layer transit-time mode and large-signal circuit simulation results are reported along with discussions. Conversion efficiencies up to ∼3.4% at ∼1.5 THz are shown to be possible.

► Monte Carlo predictions to describe transport in submicron GaN channels is flawed.
► Empirical v–E relation accounts for quasi-ballistic transport features.
► Peak velocity of 7e + 7 cm/s at ∼300 kV/cm threshold field is shown.
► Planar diodes with ∼20 nm thick channel allows feasible operating temperatures.
► With this approach efficiencies up to ∼3.4% at 1.5 THz shown possible.