Time Response of the High-field Electron Distribution Function in GaAs

Numerical calculations have been made of the high-field electron distribution function for GaAs, its small-signal frequency response and its behavior in large sinusoidal electric fields. The response speed is limited by the low scattering rate within the 〈000〉 valley. With increasing frequency the threshold field for negative conductivity rises and the negative mobility and oscillator efficiency fall. The free-electron dielectric constant is positive at high-fields, with a peak near the threshold field.