The effectiveness of two recently proposed repeated overshoot structures is investigated using Monte Carlo simulation. Results are presented showing electron velocity, energy and valley occupancy as a function of bias conditions. High local peak velocities sometimes are observed, but for a given mean field across a unit cell the average velocities are always relatively low; less than or at best equal to the steady state velocity in bulk GaAs with the same average fields. The reasons for this are explained in terms of the diffusion process.
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