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 ev aluate the ionized deep levels in n-GaAs crystals. The PHCAP measureme nts 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. Th e changes of ion densities are shown as a function of the course of th e photoquenching phenomenon. From the change of ion density of each le vel, it is shown that the generation of the 0.50 eV+E(v) level by phot oexcitation plays a vital role in the occurrence of the photoquenching phenomenon.