Lead-vacancy-related hole centers in lead tungstate crystals



After UV irradiation of PbWO4 crystals at T > 140 K in the energy range around 4.05 eV, besides the thermally stimulated luminescence (TSL) peak at ≈193 K arising from electron {Pb+ − VO} centers, a TSL peak at about 225 K appears. We suggest that this ≈225 K TSL peak arises from the thermal destruction of non-paramagnetic hole centers of the {VPb + 2h}-type (two holes trapped at the oxygen ions in the vicinity of a single lead vacancy VPb). The recombination of thermally or optically released electrons with these hole centers at T > 140 K is accompanied with green G(II) emission peaking at about 2.5 eV. The processes of photo-thermally stimulated creation of VPb-related hole centers have been studied.