A study of the PL emission mechanisms in silica glass by considering the growth of the PL

We studied the photoluminescence (PL) emission mechanisms in silica glass by considering the growth of the PL curve. The most interesting part of this work was the study of the time required to attain maximum PL intensity. This time is due to some transfer mechanism (e.g., charge-transfer or an energy-transfer transition between energy donor defect and energy acceptor defect). We observed PL bands at 1.5, 1.75, 1.9, 2.25, 2.7, 3.08, 3.15 and 4.3 eV. Although the time required to attain maximum PL intensity for the 1.75, 1.9 and 2.25 eV PL bands excited by visible light was less than the laser pulse width [full width at half maximum (FWHM)∼10 ns], the time required to attain maximum PL intensity for the 1.5, 1.9, 2.7, 3.08 and 3.15 eV bands excited by ultraviolet light was greater than the laser pulse width. These results indicate the possibility that some transfer mechanism is included in the PL mechanism for the 1.5, 1.9, 2.7, 3.08 and 3.15 eV bands excited by ultraviolet light.