Electrical conduction in PbMoO4 crystals

Abstract

The application of an electric field (300 V/cm) on PbMoO4 crystals at direct contacts generates a coloration spreading from the anode. The absorption at about 2.2 eV vanishes after annealing in air. The current‐voltage characteristic exhibits a linear relationship under special conditions. Annealing in reducing nitrogen atmosphere drastically enhances the conductivity and gives rise to the occurrence of a quadratic characteristic. Oxygen vacancies are assumed to be involved in trapping processes during the injection of carriers. A narrow peak in the photoconductivity spectrum at 380 nm is ascribed to the transition of an electron from the 6s2 state of the lead ion to the 2e molecular orbital of the oxocomplex ion with a subsequent thermal activation. Some other bands in the longwave region are correlated to (MoO4)3− centers and oxygen vacancies.

On the Origin of the Transmission Damage in Lead Tungstate Crystals under Irradiation

“…The measurement technique is described elsewhere [9]. To identify electron and hole centers, optical spectroscopy data, Thermo-Stimulated Luminescence (TSL), Thermo-Stimulated Current (TSC) and EPR spectroscopy data described in [13][14][15][16][17] have also been taken into account.…”

“…An understanding of the origin of rechargeable defects in PWO crystal comes through the study of its radiating centers. In addition to detailed investigation of lead tungstate crystal spectroscopic properties started in the seventies [13][14][15][22][23][24], a new and systematic study has been made with samples grown by different producers [8,[25][26][27][28][29][30] over the last five years which has led to a better understanding of the origin of the luminescence in PWO crystals. The luminescence appears to be due to charge transfer transitions in anionic molecular complexes WO 4 2and WO 3 .…”