EPR STUDY OF STRUCTURAL DEFECTS IN ION-IMPLANTED MULTICOMPONENT SILICATE-GLASSES

Radiation defects induced by ion bombardment of multicomponent silicate (MCS) glasses are investigated and discussed. In MCS glasses, implanted with B+, P+, N+, Cu+, Ag+, Sb+, W+ ions at energies varying between 30 and 380 keV and doses ranging from 10(13) to 10(18) ions/cm2, two types of electron paramagnetic resonance (EPR) signal, differing from those observed in gamma-irradiated samples, are found. One 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 g1 = 2.015, g(s) = 2.008 and g3 = 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 gamma-irradiation and subsequent annealing of MCS glasses implanted with Cu+ ions at energies ranging from 150 to 250 keV and doses varying between 3 X 10(14) and 1 X 10(15) ions/cm2. It is assumed that this spectrum belongs to Cu+ ions which have trapped a positive hole produced by gamma-irradiation, becoming Cu2+. MCS glasses treated by Ti-B + and Ti-P+ ion-mixing with boron doses of 6.2 X 10(15) and 3 X 10(17) ions/cm2 and phosphorus dose 2 X 10(17) ions/cm2 were studied. Ti3+ was found to have no EPR signal , although titanium results are present from Rutherford backscattering and secondary ion mass spectroscopy measurements.