E' and B-2 center production in amorphous quartz by MeV Si and Au ion implantation

Amorphous SiO2 was implanted with Si+ and Au2+ ions at energies of 4 and 3 MeV, respectively. The doses ranged from 0.3 x 10(17) to 1.5 x 10(17) ions cm(-2), and a current density of 30 muA cm(-2) was used. The formation of E ' and B-2 centers was observed for both ions by optical absorption and elec tron paramagnetic resonance (for E' defects) measurements. For Si implantat ion, there is a saturation of E'-center formation for doses higher than 1.0 x 10(17) Si cm(-2); Au implantation produces E'-center annealing for suffi ciently high doses. The heating effect due to the relatively high current d ensity induces spontaneous formation of Au nanoparticles already during the ion bombardment. The effect of subsequent thermal annealing in a reducing atmosphere at 600 and 900 degreesC on the E' and B-2 centers was also studi ed. (C) 2000 Elsevier Science S.A. All rights reserved.