Optical Absorption and Electron Paramagnetic Resonance of the E'-alpha Center in Amorphous Silicon Dioxide

TL;DR

This study combines optical absorption and EPR spectroscopy to analyze the E'-alpha defect in amorphous silicon dioxide, revealing its optical properties and relation to other defects, with implications for understanding defect states.

Contribution

The paper provides a detailed characterization of the E'-alpha defect's optical absorption band and its electronic transition, linking it to the E'-gamma center in amorphous silicon dioxide.

Findings

E'-alpha center causes a Gaussian OA band at 5.8 eV

The oscillator strength of the transition is 0.14

OA band similar to that of E'-gamma center

Abstract

We report a combined study by optical absorption (OA) and electron paramagnetic resonance (EPR) spectroscopy on the E'-alpha point defect in amorphous silicon dioxide (a-SiO2). This defect has been studied in beta-ray irradiated and thermally treated oxygen-deficient a-SiO2 materials. Our results have pointed out that the E'-alpha center is responsible for an OA Gaussian band peaked at 5.8 eV and having a full width at half maximum (FWHM) of 0.6 eV. The estimated oscillator strength of the related electronic transition is 0.14. Furthermore, we have found that this OA band is quite similar to that of the E'-gamma center induced in the same materials, indicating that the related electronic transitions involve states highly localized on a structure common to both defects.