Excitation pattern of the blue emission in Ge-doped silica

The luminescence of Ge-doped glassy SiO2 has been investigated at room temperature using a deuterium lamp as the excitation source in the ultraviolet and vacuum ultraviolet energy range. Two emission bands are observed around 3 and 4 eV as the excitation increases from 4.5 to 8 eV. The peak shift and bandwidth broadening of the emission around 3 eV indicate the overlapping of several bands. We carried out a Gaussian best-fit approach of the detected spectra and extracted the excitation spectra of three distinct emission: a 2.9 eV band with two excitation channels at 4.7 and 5.3 eV and no contribution above 6 eV and the well-known composite beta-band (3.1 eV). The latter is resolved into two Gaussian components whose excitation spectra present three main excitations around 5.1, 6.5 and 7.3 eV. (C) 2003 Elsevier Science B.V. All rights reserved.