Materials Research Bulletin, Vol.89, 139-149, 2017
Temperature dependence of luminescence intensity in ZnMoO4 crystals
Luminescence of ZnMoO4 crystals (of stoichiometric composition, with excess of molybdenum and doped with tungsten) under X-ray irradiation in the temperature interval from 4 to 400 K was studied. The difference in the composition has little influence on the luminescence properties of the samples. An increase of the 1.93 eV emission band intensity was observed in the temperature interval from 8 K to 90 K. Two mechanisms, concurrence with excitonic emission and concurrence with non-radiative recombination channel, were considered to explain the observation. Theoretical formulas were obtained to describe the temperature dependence of luminescence intensity. The experimental data are well described by the developed theoretical model which assumes recombination of free charge carriers with carriers of opposite sign localized on shallow traps. The high temperature quenching of luminescence is well described by the Mott formula. (C) 2017 Elsevier Ltd. All rights reserved.
Keywords:ZnMoO4 crystals;Luminescence under X-ray excitation;Luminescence spectra;Excitonic emission;Recombination emission