Photo- and radioluminescence of lithium hafnate Li 2HfO 3

Abstract

Photoluminescence, excitation and pulse cathode luminescence spectra, and decay kinetics of lithium hafnate Li 2HfO 3 were investigated at temperatures 300 and 7.5 K. Time-resolved luminescence spectra were excited with synchrotron radiation in UV-VUV range. Strong emission with the peak position at 4.42 eV and with the decay time in μs range was revealed at T = 7.5 K. The emission was attributed to radiative decay of self-trapped excitons (STE). The features observed in the excitation spectra at 6.6 eV were likely to take place because of the exciton formation, with inter-band transitions dominating at 6.7 eV. Crystal structure defects underpin the luminescence spectra formation at room temperature in the frame of vacancy model. © 2012 Elsevier B.V. All rights reserved.