Effects of doping, gamma irradiation, and annealing on the temperature dependence of the photocurrent through bismuth titanate crystals

The separate and combined effects of doping, annealing, and gamma irradiati on on the temperature-dependent photocurrent through nominally undoped and doped sillenite-type crystals were investigated between 77 and 300 K. The r esults were interpreted using a band-structure model describing the recombi nation processes involved in terms of deep slow and fast recombination cent ers (r- and s-centers) and shallow traps. The electron transitions to recom bination centers were shown to be controlled by the trap level E-1. The the rmal stability of radiation-induced defects was assessed.