Four types of electron traps in ${\mathrm{PbWO}}_4,$ based on regular W sites perturbed by oxygen vacancies, are identified by electron spin resonance (ESR). The analysis of the ESR spectra parameters $(g$-factor values and principal-axes orientations) shows that the revealed centers are $({\mathrm{WO}}_3{)}^{-}$ vacancy-containing complex anions associated with a defect in the Pb sublattice: $({\mathrm{WO}}_3{)}^{-}-A_{\mathrm{Pb}}$ complexes. Two of the centers $({\mathrm{W}}_1$ and ${\mathrm{W}}_2)$ are thermally stable up to 350–370 K, while the other two $({\mathrm{W}}_3$ and ${\mathrm{W}}_4)$ are stable only up to 270–290 K. Above these temperatures the trapped electrons become free and recombine with localized holes, giving rise to a composite TSL glow peak at $T\approx 323\mathrm{K}$ (characterized by a trap depth of 0.9 eV evaluated by the initial rise method) and to a weaker TSL structure at $T\approx 365\mathrm{K}.$ The correspondence between $({\mathrm{WO}}_3{)}^{-}-A_{\mathrm{Pb}}$ centers and TSL peaks is supported by their similar room temperature time decays, and by the similar dependences of ESR and TSL signals upon annealing treatments. A scheme of local electronic levels in the band gap of ${\mathrm{PbWO}}_4$ is proposed.

• Received 26 November 2002

DOI:https://doi.org/10.1103/PhysRevB.67.205102