EPR study of structural defects in ion-implanted multicomponent silicate glasses

Abstract

Radiation defects induced by ion bombardment of multicomponent silicate (MCS) glasses are investigated and discussed. In MCS glasses, implanted with B +, P +, N +, Ag +, Sb +, W + ions at energies varying between 30 and 380 keV and doses ranging from 10 13 to 10 18 ions/cm 2, two types of electron paramagnetic resonance (EPR) signal, differing from those observed in γ-irradiated samples, are found. Ond of them, denoted by S, is a narrow, almost symmetric signal with g-values ranging from 2.0018 to 2.0034 which is attributed to a vacancy-type defect with one dangling silicon bond. The other signal, denoted by A, is an anisotropic line with g 1 = 2.015, g s = 2.008 and g 3 = 1.999 (±0.001) which is ascribed to interstitial oxygen species. It is shown that the appearance of the S- and A-signals and their relative intensity depend on the energy, dose and atomic mass of the incident ions. It is also found that an anisotropic EPR spectrum with g = 2.29 ± 0.01 and g = 2.04 ± 0.01 appears after γ-irradiation and subsequent annealing of MCS glasses implanted with Cu + ions at energies ranging from 150 to 250 keV and doses varying between 3 × 10 14 and 1 × 10 15 ions/cm 2. It is assumed that this spectrum belongs to Cu + ions which have trapped a positive hole produced by γ-irradiation, becoming Cu 2+. MCS glasses treated by TiB + and TiP + ion-mixing with boron doses of 6.2×10 15 and 3×10 17 ions/cm 2 and phosphorus dose 2 × 10 17 ions/cm 2 were studied. Ti 3+ was found to have no EPR signal, although titanium results are present from Rutherford backscattering and secondary ion mass spectroscopy measurements.