Exciton emission and defect formation in yttrium trifluoride

Two intrinsic emission bands at 220 and 280 nm have been detected in nominally pure YF3 powders at 10 K. Excitation spectra for both emissions have a sharp peak at 12 eV near the edge of interband transition. Observed emissions are assigned to the radiative decay of self-trapped excitons in YF3. The strong thermal quenching of intrinsic luminescence was observed at temperature above 120 K. It was supposed that non-radiative decay of self-trapped exciton at high temperatures lead to defect formation in YF3. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)