18 March 2002 Variable porous structure of laser-ablated silicon nanocluster films and its influence on photoluminescence properties
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Proceedings Volume 4636, Nanoscience Using Laser-Solid Interactions; (2002) https://doi.org/10.1117/12.459735
Event: High-Power Lasers and Applications, 2002, San Jose, California, United States
Abstract
Si/SiOx films were fabricated by Pulsed Laser Ablation from a silicon target in a residual gas. The films were crystalline with minimal grain size of 2-4 nm and had a porous morphology. The film structure was found to be extremely sensitive to deposition conditions with porosity depending on the gas pressure during the deposition. In particular, the increase of helium pressure from 0.2 to 4 Torr in different depositions led to a gradual porosity (P) increase from 10% to 95%. The porosity increase was accompanied by a slight increase of mean crystal size in the deposit. It has been established that photoluminescence (PL) properties were different for films with different porosities. For low porous films (P < 40 %), we observed PL signals with peak energies between 1.6 and 2.12 eV depending on helium deposition pressure. In contrast, PL properties of highly porous films (P > 40%) were mainly determined by post-deposition oxidation phenomena. They led to an enhancement of PL bands around 1.6-1.7 eV and 2.2-2.3 eV, which were independent of deposition conditions. Similar 2.2-2.3 eV signals were observed after strong film oxidation through a thermal annealing of films in air or through a silicon ablation in oxygen-containing atmosphere. Mechanisms of film formation and PL origin are discussed.
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Andrei V. Kabashin, Jean-Philippe Sylvestre, Sergiy Patskovsky, Michel Meunier, "Variable porous structure of laser-ablated silicon nanocluster films and its influence on photoluminescence properties", Proc. SPIE 4636, Nanoscience Using Laser-Solid Interactions, (18 March 2002); doi: 10.1117/12.459735; https://doi.org/10.1117/12.459735
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