Formation and photosensitivity of defects in Se implanted silica

Silica was implanted with Se ions at 4 MeV with nominal doses of 0.1, 0.3, 0.5, 1.0 and 3.0 × 10¹⁶ ions/cm². The optical absorption was measured from 1.8 to 6.2 eV. Bands at 5.9 and 5 eV are observed in the absorption spectra. The magnitude of the absorption increases with increasing dose but the increase is variant with dose. Bands at 2.6, 3.7 and 4.8 eV are attributed to the presence of the Se. The 0.3 and 1.0 × 10¹⁶ samples were exposed to 5 eV KrF excimer irradiation with a fluence of 150 mJ/cm² per pulse for pulse totals of 1.5 J/cm². Bleaching of the 5 and 5.9 eV bands is observed and is attributed to the bleaching of defects at 5, 5.5 and 5.9 eV.