@article {Tull:528,
	title = {Formation of silicon nanoparticles and web-like aggregates by femtosecond laser ablation in a background gas},
	journal = {Appl. Phys. A},
	volume = {83},
	year = {2006},
	pages = {341{\textendash}346},
	abstract = {We show that the mechanism of nanoparticle formation during femtosecond laser ablation of silicon is affected by the presence of a background gas. Femtosecond laser ablation of silicon in a H2 or H2S background gas yields a mixture of crystalline and amorphous nanoparticles. The crystalline nanoparticles form via a thermal mechanism of nucleation and growth. The amorphous material has smaller features and forms at a higher cooling rate than the crystalline nanoparticles. The background gas also results in the suspension of plume material in the gas for extended periods, resulting in the formation (on a thin film carbon substrate) of unusual aggregated structures including nanoscale webs that span tears in the film. The presence of a background gas provides additional control of the structure and composition of the nanoparticles during short pulse laser ablation. PACS 81.16.-c},
	doi = {10.1007/s00339-006-3502-7},
	url = {/files/mazur/files/rep_528.pdf},
	author = {B. R. Tull and J. E. Carey and M. A. Sheehy and Friend, C. M. and Mazur, E.}
}
