Optically Driven Domain Instability and High-Frequency Current Oscillations in Photoexcited GaAs under Nonuniform Electron Heating

Fast domain instabilities induced by light-interference pattern in dc-biased semi-insulating GaAs are investigated. Current oscillations in GHz-frequency range are observed due to nonuniform electron heating and domains formation in light-induced grating. Characteristic features of the oscillations under various experimental conditions are presented. Numerical calculations based on the hot-electron hydrodynamic model are used to explain the observed nonlinear features under various external bias and periods of the grating.