Publication Date:
2011-06-24
Description:
The properties of electron paramagnetic resonance (EPR) signal of oxygen dangling bonds in amorphous SiO 2 ("non-bridging oxygen hole centers", NBOHC) in excimer laser-irradiated amorphous SiO 2 were studied in the temperature range 20K to 295K. NBOHCs strongly affect optical and chemical properties of amorphous SiO 2 -based (nano) structures and their surfaces. The behaviour of their EPR signal is complicated due to a nearly degenerate electronic ground state. It was found that EPR signal has a non-Curie (~1/T) T-dependence down to 40K, indicating that EPR-based concentration estimates routinely obtained at T = 77K underestimate the center concentrations at least by a factor of 1.7. The estimates of NBOHC concentration, based on EPR, are typically ~10 times lower than those derived from optical spectroscopy, evidently due to incomplete accounting for temperature, microwave saturation and due to degenerate ground state coupled to disorder effects. T...
Print ISSN:
1757-8981
Electronic ISSN:
1757-899X
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
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