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

Abstract

Amorphous SiO 2 was implanted with Si + and Au 2+ ions at energies of 4 and 3 MeV, respectively. The doses ranged from 0.3×10 17 to 1.5×10 17 ions cm −2, and a current density of 30 μA cm −2 was used. The formation of E′ and B 2 centers was observed for both ions by optical absorption and electron paramagnetic resonance (for E′ defects) measurements. For Si implantation, there is a saturation of E′-center formation for doses higher than 1.0×10 17 Si cm −2; Au implantation produces E′-center annealing for sufficiently high doses. The heating effect due to the relatively high current density 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°C on the E′ and B 2 centers was also studied.