Photocapacitance investigation of the ionized levels in n-GaAs crystals and its association with the ‘‘photoquenching phenomenon’’

Results are reported of a photocapacitance (PHCAP) investigation to evaluate the ionized deep levels in n-GaAs crystals. The PHCAP measurements reveal two sorts of ionized deep levels at 0.50 and 0.74 eV above the valence band at 45 K only during the photoquenching phenomenon. The changes of ion densities are shown as a function of the course of the photoquenching phenomenon. From the change of ion density of each level, it is shown that the generation of the 0.50 eV+Ev level by photoexcitation plays a vital role in the occurrence of the photoquenching phenomenon.