Luminescence and absorption in type III silica implanted with multi-energy Si, O and Ar ions

Some effects on the photoluminescence band at 4.4 eV and optical bands in the 4.8–5.2 eV range produced by multi-energy (highest energy 320 keV) Si and O implantations in (type III) silica have been measured. Samples were implanted with multi-energy Si ions, with O ions, and with Ar ions to form a region of constant concentration. The depth of this region was ∼600 nm with the transition region, from zero to constant concentration being ∼100 nm thick. Concentrations ranged from approximately 0.02–2.1 at.%. We propose that in these samples photoluminescence and absorption bands due to the various combinations of oxygen vacancies will increase with increasing Si concentration with related O related defects changing at much smaller rates. In the absorption spectra of samples implanted with O, bands associated with oxygen related defects increase with increasing concentration, while those due to various forms of O vacancies will change at much smaller rates. To test the hypothesis that the observed absorption bands in the 4.8–5.2 eV range are the source of the 4.4 eV luminescence band, we have compared the changes in the three absorption bands in the 4.8–5.2 eV range with changes in the luminescent intensity of the 4.4 eV band. Based on the intensity of the luminescence in the Si implanted samples compared to the intensity in the Ar and O implanted samples and the expectation that the Si implanted samples will have a preponderance of oxygen deficient sites, we conclude that the 4.4 eV emission is due to oxygen deficient defects. The changes in the amplitude of the 5.01 eV absorption band is more similar to the changes in the 4.4 eV emission than to any other band in the O samples. However, none of the bands have a convincing correlation with the 4.4 eV emission.