Abstract
A dynamic systems approach to nonlinear charge transport and electrical instabilities in semiconductors is presented, and illustrated by specific examples of physical transport mechanisms which yield oscillatory instabilities: Impact ionization of shallow impurities at liquid helium temperature as a mechanism for selfgenerated chaotic dielectric relaxation oscillations; Poole-Frenkel emission from deep levels at room-temperature as a mechanism for low-frequency oscillations in semiinsulating GaAs; Impact ionization and optical phonon emission as a mechanism for global bifurcations and hysteresis of oscillations in p-Ge; Breathing current filaments.