Positron annihilation spectroscopy was used to depth profile the modification of

intrinsic structural nanovoids in silica glass implanted with Ar+ ions at different

fluences and implantation energies. Beyond an expected defect distribution below

the ion projected range Rp, a second defect distribution extending more than two

times deeper than Rp was revealed. This second defective layer was found to be

related to recoiled oxygen atoms whose diffusion was probably increased by the

stress gradient induced by the compaction of the first layer.

Direct Evidence by Positron Annihilation Spectroscopy of Defect Distributions

Deeper than Rp in Ar+ Implanted Silica Glass. P.Mazzoldi, G.Mattei, L.Ravelli,

W.Egger, S.Mariazzi, R.S.Brusa: Journal of Physics D, 2009, 42[11], 115418