STUDY OF CHARGE CARRIER TRAPPING IN SOLUTION-GROWN ALPHA-HGL2 CRYSTALS BY THERMALLY STIMULATED CURRENTS

Alpha-Hgl2 crystals grown in solution, crystals irradiated by x- or ga mma-rays, crystals aged in air, crystals aged after being polarized in a high DC field, and crystals stored in an iodine atmosphere were stu died by thermally stimulated currents (TSC). The general TSC spectrum of the crystals shows two peaks: at 170 and 230 K. X-ray irradiation g enerates deep-donor-type traps and decreases the lifetime of the charg e carriers. Gamma-ray irradiation introduces a large number of deep tr aps closely spaced in energy. By aging the crystals in air deep donor traps are introduced into a narrow layer close to the surface of the c rystals. Crystals aged in air and polarized in a high DC field show a depletion of the concentration of the deep donor traps in the active z one close to the surface induced by the field. The storage of the crys tals in an iodine atmosphere prevents their degradation by aging. Appa rently iodine diffusion into the crystals suppresses the slight Hg-ric h deviation from the stoichiometry in crystals.