OPTICALLY INDUCED RECOVERY BY NEAR BAND-GAP PHOTONS (1.4 EV-LESS-THAN-H-NU-LESS-THAN-1.5 EV) OF EL2 LEVEL FROM ITS METASTABLE STATE IN SEMIINSULATING GAAS

The study of the recovery of the EL2 related photocurrent by photons of the near-band gap spectral range (1.4-1.51 eV), after photoquenching reveals that the amount of EL2 levels that can be quenched depends on the excitation conditions. In particular light of the 1.44 eV, photocurrent band, produces an increase in the amount of EL2 quenchable levels. This is discussed in terms of an actuator level, whose charge state controls the transition to the metastable state and on the other hand ensures the electrical compensation when EL2 is in the metastable configuration, for which it is in its neutral charge state, and hence unable to compensate the ionized shallow acceptors.