Optical Nonlinearities in Bulk GaAs Determined by EL2 Defect

Time-resolved studies of light diffraction on free carrier phase gratings and light absorption in subnanosecond time domain were carried out in two distinct areas of semi-insulating GaAs with high and low growth-defect density. Numerical analysis was performed in order to reveal the role of EL2 defect in carrier generation and transport. The possibility of transient grating technique to study various defect-governed carrier relaxation processes were demonstrated experimentally.