HIGH-FREQUENCY AC CONDUCTIVITY OF HOT-ELECTRONS IN BULK SEMICONDUCTORS

On the basis of the balance-equation transport theory we have carried out a detailed calculation of the small-signal high-frequency conducti vity for n-doped bulk GaAs systems under a do bias. Contributions from impurity and phonon scatterings are taken into account. Attention has been paid to the role of electron bulk plasma modes, which give rise to a significant deviation of the high-frequency conductivity from the Drude formula at low de bias. It is pointed that when the de bias inc reases the plasma effect is suppressed by the rise of the electron tem perature while the role of the electron temperature oscillation enhanc es, leading to an appreciable peak in the real part of the conductivit y at low frequency.