Self-limiting and complete oxidation of silicon nanostructures produced by laser ablation in water
- Autori: Vaccaro, L.; Popescu, R.; Messina, F.; Camarda, P.; Schneider, R.; Gerthsen, D.; Gelardi, F.; Cannas, M.
- Anno di pubblicazione: 2016
- Tipologia: Articolo in rivista (Articolo in rivista)
- OA Link: http://hdl.handle.net/10447/216602
Oxidized Silicon nanomaterials produced by 1064 nm pulsed laser ablation in deionized water are investigated. High-resolution transmission electron microscopy coupled with energy dispersive X-ray spectroscopy allows to characterize the structural and chemical properties at a sub-nanometric scale. This analysis clarifies that laser ablation induces both self-limiting and complete oxidation processes which produce polycrystalline Si surrounded by a layer of SiO2 and amorphous fully oxidized SiO2, respectively. These nanostructures exhibit a composite luminescence spectrum which is investigated by time-resolved spectroscopy with a tunable laser excitation. The origin of the observed luminescence bands agrees with the two structural typologies: Si nanocrystals emit a μs-decaying red band; defects of SiO2 give rise to a ns-decaying UV band and two overlapping blue bands with lifetime in the ns and ms timescale.