Abstract
When a 355-nm pulsed laser light was focused on a polished surface of single crystal silicon (100) in an atmosphere of N2 gas, some visible photoluminescent silicon nanocrystallites deposited at the bottom and in the vicinity of a hole produced by intense laser ablation. The emission band of these Si-particles, when excited with an Ar ion laser (λ=514 nm), had a maximum intensity at 590 nm (2.1 eV)-680 nm (1.8 eV) varying systematically in submillimeter units of their distance from the hole. Similar irradiation was carried out under two other gas atmospheres (Ar and O2) and in vacuo (<1.33×10-4 Pa) and the photoluminescent character of the deposited compounds were examined by microprobe photoluminescence spectroscopy. The luminescent characters (band shape and/or band peak position) were found to depend also on these gas atmospheric conditions.
