Distributions of self-trapped hole continuums in silica glass

Photobleaching of self-trapped holes STH in low temperature UV-irradiated silica glass has been investigated by the electron spin resonance method. The bleaching time dependence of the decay of two kinds of STH, STH1, and STH2, could be well fitted by the stretched exponential function, and STH2 has a quicker decay than STH1. On the other hand, the decay becomes significant large when the photon energy increases from 1.5 to 2.0 eV, and then keeps constant with a further increase of photon energy. The distributions of the STH continuums are estimated at the positions on top of the valence band, being 1.66±0.27 eV for STH1 and 1.63±0.33 eV for STH2. A possible recombination mechanism is proposed to explain the decay of STH signals. © 2006 American Institute of Physics. DOI: 10.1063/1.2216350