Abstract
Electron traps based on regular Pb sites perturbed by oxygen vacancies in high purity undoped have been revealed and studied by electron spin resonance (ESR) and thermally stimulated luminescence (TSL) measurements. Detailed analysis of ESR spectra parameters factor, hyperfine, and superhyperfine structures) along with the variation of the concentration after annealing in inert and oxygen atmospheres had shown that revealed centers are complexes. The centers are created in two ways: (i) by direct trapping of the electrons from the conduction band under x-ray or ultraviolet irradiation at (ii) by retrapping of electrons freed from unperturbed centers after irradiation at followed by heating at Above centers are thermally ionized, giving rise to a TSL glow peak due to the recombination of freed electrons with localized holes. The emission spectrum of the TSL features one band peaking at around The temperature dependence of both TSL and ESR intensities has been analyzed using a first order recombination model: the thermal ionization energy of centers turns out to be The role of centers in the processes of carrier trapping and recombination of nonequilibrium carriers in the lattice is briefly discussed.
- Received 15 March 2001
DOI:https://doi.org/10.1103/PhysRevB.64.165102
©2001 American Physical Society