Electric-Field-Induced Phonon-Assisted Tunnel Ionization from Deep Levels in Semiconductors

Abstract
A quantum theory is presented to explain the anomalously high ionization rates observed from some point defects in semiconductors in regions of large electric field. This spectacular enhancement is shown to originate from phonon-assisted tunnel ionization. Comparison with experiment is made in the case of four defects in GaAs and GaP and results in values of the Franck-Condon shift and effective phonon frequency that are in very good agreement with values deduced from other experiments.