Sequential light irradiation and two-stage photoquenching in GaAs:EL2

The phenomenon of two-stage photoquenching of EL2 defect in semi-insulating GaAs [V.Pandian and V. Kumar, J. Appl. Phys. 70, 5114 (1991)] is further investigated by sequentially irradiating the sample with different energy photons in the quenching band at constant temperature. The results of the new experiments, which are similar to the sequential quenching experiments with fixed photon energy at different temperatures, support the conclusion that the two-stage quenching.may be related to the possible lattice strain mediated cooperative structural distortion arising out of transition of EL2 to the metastable state