The Effect of Double-Peak Velocity Characteristics on Gunn Oscillations

Gunn diodes use the Ridley-Watkins-Hilsum effect to generate low noise millimeter wave signals for communication and measurement applications. A perturbation study of the double Ridley-Watkins-Hilsum effect on Gunn oscillations is conducted in order to investigate the potential performance improvements for Gunn diodes. Double-peak velocity characteristics representative of cryogenic, compensated GaAs are provided to a charge transport simulation of a simplistic Gunn diode. The effects of double-peak velocity characteristics on frequency response and domain formation are observed. A 1.6 μm device shows a 7-fold improvement in tunability with a decrease in current efficiency. A 5 μm device shows 60% increase in tunability. Hysteresis is exaggerated and a splitting domain is observed. The increase in the tunable frequency range is attributed to the absorption rate, transit length modulation, and the distribution resulting from past biases.