NONEQUILIBRIUM PHONON EFFECTS ON THE TRANSIENT HIGH-FIELD TRANSPORT REGIME IN INP

We present a detailed investigation of the transient transport regime in InP at room temperature based on an original method to solve numeri cally the coupled hot-phonon-hot-carrier time-dependent Boltzmann equa tions for the case of a steplike high de electric field pulse. The met hod enables a study of the perturbation of the phonon distribution fun ction induced by hot carriers and the corresponding modifications of t he carrier distribution function. The numerical accuracy of the method is far beyond other existing methods, and, as a consequence, the time behavior of the main transport parameters can be resolved in great de tail. The presence of nonequilibrium phonons is found to be responsibl e for an overall increase in the time duration of the transient regime . Modifications in the time evolution of the main transport parameters are also observed; in particular, the carrier drift velocity exhibits a second overshoot for electric fields near the threshold value for n egative differential mobility. The sensitivity of the results to the v alue of the phonon relaxation time is also discussed.