Effect of swift heavy ions on silicon nanostructures

The influence of irradiation with Xe ions, 130 MeV on SiO₂ layers, either implanted with Si or implanted with Si and subsequently subjected to annealing at temperature of 1100degC was examined by photoluminescence. Initially, the photoluminescence band near 660 nm was observed in non-annealed layers. The irradiation with the low doses of Xe ions didn´t change its intensity. The band disappeared after passivation of the layers in reducing ambient and new photoluminescence band appeared near 770 nm. In the annealed layers an intense photoluminescence band with maximum of 770 nm was observed, typical to quantum-size silicon nanocrystals. This photoluminescence quenched by irradiation with Xe ions when ~ 1 displacement per nanocrystal according to calculations was introduced. Further increase in the dose of Xe ions leads to appearance and growth of photoluminescence near 660 nm. Because amorphization of nanocrystals was impossible after the doses used, the band near 660 nm was associated with the damaged nanocrystals. Taking into account that such band was observed immediately after implantation of silicon ions, whose elastic losses were much more than Xe ions, one can conclude, that the influence of Xe irradiation is connected with their ionization losses.