Nano Archive

Effects of temperature on electron paramagnetic resonance of dangling oxygen bonds in amorphous silicon dioxide

Skuja, L and Kajihara, K and Hirano, M and Silins, A and Hosono, H (2011) Effects of temperature on electron paramagnetic resonance of dangling oxygen bonds in amorphous silicon dioxide. IOP Conference Series: Materials Science and Engineering, 23 (1). 012016.

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Official URL: http://stacks.iop.org/1757-899X/23/i=1/a=012016

Abstract

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. The EPR signal of NBOHCs shows a strong microwave saturation at T<40K which allows for a high-sensitivity detection by 2nd-harmonic EPR registration techniques. Using it, the low intensity low-field wing of the EPR signal was shown to extend to g values as large as g = 2.4.

Item Type:Article
ID Code:11272
Deposited By:Prof. Alexey Ivanov
Deposited On:01 Nov 2011 23:30
Last Modified:02 Nov 2011 00:47

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