A. Hafstaetter et al., The role of defect states in the creation of intrinsic (WO4)(3-)centers inPbWO4 by sub-bandgap excitation, RADIAT MEAS, 33(5), 2001, pp. 533-536
Intrinsic (WO4)(3-) centers can be created in lead tungstate by irradiation
with light having energies well below the bandgap, i.e. the threshold for
excitation of the blue tungstate luminescence. Detailed photo-ESR studies s
how that this happens by ionization of defect states in the bandgap which h
ave been prefilled by suitable radiation. Depending on the energy depth of
the respective defects a wavelength between near-infrared and near-UV is ne
cessary for the ionization process. A simultaneous production of different
electron centers is observed via participation of the conduction band. This
allows an easy determination of the trap level energies. (C) 2001 Elsevier
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