On the geometrical tunabililty of THz Gunn-like oscillations in InGaAs/InAlAs slot diodes

By using an ensemble Monte Carlo simulation we study the influence of the bias, the recess-to-drain distance, recess length and δ-doping on the frequency of the ultra-fast Gunn-like oscillations f_G found in InGaAs/InAlAs slot diodes. A minimum carrier concentration is needed under the recess for the process to start up. Thus, a δ-doping larger than 5×10¹² cm⁻² is necessary, but too high values of this parameter reduce the oscillation frequency. As expected, by shortening the devices (small recess and recess-to-drain lengths) f_G increases. As concerns the DC voltage, the optimum conditions correspond to biases exceeding as less as possible the threshond voltage for the onset of intervally transfer.