Monte Carlo Investigation of THz Oscillations in InAlAs/InGaAs Heterostructures by Means of Current and Voltage Noise Spectra

摘要

We present a microscopic analysis of current and voltage fluctuations in InAlAs/InGaAs diodes and transistors. An ensemble Monte Carlo simulation is used for the calculations. We analyze the origin of the marked THz oscillations appearing when the drain-source bias surpasses 0.5 V. This effect is apparently caused by the presence of Gunn-like oscillations whose dynamics is controlled by ballistic GAMMA-valley electrons in the channel. These carriers are capable to reach extremely high velocities due to (i) the influence of degeneracy effects, which significantly reduces the rate of scattering mechanisms, and (ii) the presence of the recess, which strongly accelerates electrons, launching them with high velocity into the drain region.