Highly charged ion bombardment of silicon surfaces

Visible photoluminescence from Si(100) surfaces irradiated by highly charged ions has recently been reported [1]. In an attempt to reproduce these results, highly charged ion-irradiated silicon samples were prepared at the Electron Beam Ion Trap at the National Institute of Standards and Technology. Two highly sensitive fluorescence detection schemes were employed, both using ultraviolet light from an argon-ion laser for excitation. In the first detection scheme, the Xe44+-Si(100) samples were excited by the ultraviolet light while a spectrograph equipped with a liquid nitrogen-cooled charge-coupled device camera detected the fluorescence. The second detection scheme was a high throughput laser-scanning confocal microscope equipped with a photon-counting photomultiplier tube. We characterized the sensitivities in each detection scheme, allowing the assessment of the photoluminescence efficiency of Xe44+-Si(100). No photoluminescence was detected in either setup.