In situ observation of the generation and annealing kinetics of E' centers induced in amorphous SiO2 by 4.7eV laser irradiation

TL;DR

This study investigates the in situ formation and annealing of E' centers in amorphous SiO2 caused by 4.7 eV laser irradiation, revealing the dynamics of defect generation and hydrogen-related annealing processes.

Contribution

It provides new insights into the real-time kinetics of E' center generation and annealing, highlighting the role of hydrogen and a common precursor in defect formation.

Findings

E' centers are generated and decay via hydrogen reactions.

Hydrogen-related annealing occurs during irradiation, competing with defect creation.

Saturation concentrations of E' and H2 are proportional, indicating a linked generation process.

Abstract

The kinetics of E' centers induced in silica by 4.7eV laser irradiation was investigated observing in situ their optical absorption band at 5.8 eV. After exposure the defects decay due to reaction with diffusing molecular hydrogen of radiolytic origin. Hydrogen-related annealing is active also during exposure and competes with the photo-induced generation of the centers until a saturation is reached. The concentrations of E' and H2 at saturation are proportional, so indicating that the UV-induced generation processes of the two species are correlated. These results are consistent with a model in which E' and hydrogen are generated from a common precursor Si-H.