Characteristic red photoluminescence band in oxygen-deficient silica glass

We studied a red photoluminescence (PL) band at about 1.8 eV with full width at half maximum of 0.2–0.4 eV in a series of oxygen deficient-type silicas before and after γ irradiation. The decay lifetime of the PL was estimated to be about 200 ns. The PL excitation peak was found to be located at 2.1 eV. The intensity of the 1.8 eV band was enhanced by about 100 times after γ irradiation up to a dose of 10 MGy. These results suggest that the 1.8 eV PL is associated with oxygen deficient states in silica glass, which were introduced during manufacture and were enhanced further by the γ irradiation. Comparison of the PL properties was made with other luminescent Si-based materials in terms of the peak energy, lifetime, and temperature dependence.