Time-resolved photoluminescence in amorphous silicon dioxide

We report time-resolved measurements of photoluminescence in bulk a-${\mathrm{SiO}}_2$ using 7.9- and 6.4-eV excitation. Time-resolved spectra have been obtained at room temperature and 25 K, and the intensity and decay rates of various luminescence bands have been measured as a function of temperature. Bands at 1.9, 2.2, 2.7, and 4.3 eV are identified. In addition, there is a very broad luminescence peaking between 3–4 eV but extending to below the 1.5-eV cutoff of our measurements. We have also measured photoluminescence in crystalline quartz and in a thermally grown oxide. Both the 4.3- and 1.9-eV bands are seen in the thermal oxide, but the 2.7-eV band is absent. In the crystal, the 1.9-eV band is absent.