New intrinsic oxygen related defect bands in oxygen implanted silica

Type III silica samples were implanted with O using a multi-energy process that produced a layer of constant concentration to within ± 5% beginning ~ 80 nm from the surface and extending to ~ 640 nm below the surfaces of samples. The concentrations in the layer ranged from 0.035 atomic percent to ~ 2.1 atomic percent. The optical absorption was measured from 2 to 6.5 eV. The absorption due to the implanted ions was analyzed using the difference spectra of the various samples. These difference spectra showed that optical bands at ~ 4.7 eV, 5.35 eV, and ~ 6.2 eV were a primary result of O implantation. Based on these data, we attribute these bands to O-related centers. Comparison of the difference spectra of the O samples with those of Si samples implanted to approximately the same concentrations showed that bands at the three energies in the spectra of the O samples were not observed in the spectra of the Si samples. Based on the spin concentrations of peroxy radicals, spin concentrations of E′γ, and optical absorption coefficients at 4.8–5.0 eV and at 5.83 eV, the oscillator strengths of the peroxy band (~ 4.8 eV) was estimated, from the oscillator strength of the absorption band at 5.83 eV to be < 0.014.

Research Highlights
► Implanted silica has optical bands at 5.35 and 6.2 eV not previously resolved.
► These new bands are due to differing atomic configurations of O in the silica.
► These bands are not observed in similar Si implanted silica.
► The oscillator strength of the POR absorption band is estimated to be f < 0.014.