PHOTOINDUCED OXYGEN-VACANCY RELATED CENTERS IN PbWO 4 : ELECTRON SPIN RESONANCE AND THERMALLY STIMULATED LUMINESCENCE STUDY.

Using electron spin resonance (ESR) and thermally stimulated luminescence (TSL) three different electron traps based on regular W sites perturbed by oxygen vacancies have been identified in PbWO 4 . Analysis of ESR spectra parameters ( g -factor values and principal axes orientations) has shown that revealed centers are (WO 3 ) - vacancy containing complex anions associated with a defect in Pb sublattice: (WO 3 ) - -A Pb complexes. One of the centers (W 1 ) is thermally stable up to 350-370 K, while the other two (W 2 and W 3 ) only to 270-290 K. Above these temperatures trapped electrons become free and recombine with localized holes, giving rise to TSL glow peaks at T\approx 323\,\hbox{K} and 365\,\hbox{K} . Using the initial rise method the 323\,\hbox{K} TSL peak-shape was fitted allowing the first order recombination kinetic that gives trap parameters E = 0.88\,\hbox{eV} and s\simeq 5\ast 10^{12}1/\hbox{s} . [ABSTRACT FROM AUTHOR]