Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9586320 | Journal of Luminescence | 2005 | 8 Pages |
Abstract
Luminescence and excitation spectra as well as their temperature dependence were investigated for nominally pure yttrium trifluoride powders using synchrotron radiation. Broad emission bands in VUV-visible spectral range were observed under excitation above 11Â eV in YF3 at 10Â K. At least three emission bands were distinguished peaking at 5.6Â eV (220Â nm), 4.5Â eV (280Â nm) and 3.1Â eV (400Â nm). It was shown that the emission bands at 5.6Â eV (220) and 4.5Â eV (280Â nm) are intrinsic but the long wavelength emission at 3.1Â eV (400Â nm) is of extrinsic nature. The excitation spectra for the two intrinsic luminescence bands have their individual features, but in both cases a sharp peak at the fundamental absorption edge is observed. This fact as well as a large Stokes shift of intrinsic luminescence (more than 5Â eV) and a large width of the emission bands (near 1Â eV) allows us to assign the 4.5Â eV (280Â nm) and 5.6Â eV (220Â nm) emission to the radiative decay of self-trapped excitons in YF3. The strong influence of temperature on the intrinsic luminescence, observed at temperatures above 120Â K, are used to evaluate the activation energy of thermal quenching.
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Authors
V. Pankratov, M. Kirm, H. von Seggern,