Photochemical generation of E′ centres from Si–H in amorphous SiO2 under pulsed ultraviolet laser radiation

In situ optical absorption spectroscopy was used to study the generation of E′ centres () in amorphous SiO2 occurring by photo-induced breaking of Si–H groups under 4.7 eV pulsed laser radiation. The dependence on laser intensity of the defect generation rate is consistent with a two-photon mechanism for Si–H rupture, while the growth and saturation of the defects are conditioned by their concurrent annealing due to a reaction with mobile hydrogen arising from the same precursor. A rate equation is proposed to model the kinetics of the defects and is tested on experimental data.