In:
Laser and Particle Beams, Hindawi Limited, Vol. 31, No. 3 ( 2013-09), p. 539-545
Abstract:
Generation and evolution of plasma during femtosecond laser ablation of silicon are studied by steady-state and time-resolved spectroscopy in air, N 2 , SF 6 , and under vacuum. The plasma is generated faster than 200 ps (time resolution of our experiment) after excitation and mainly contains atoms and monovalent ions of silicon. Time-resolved spectra prove that silicon ions are faster than the silicon atoms which may be attributed to Coulomb repulsion and a local electric field when they are ejected from the silicon surface. During plasma evolution, ambient gas causes a confinement effect that enhances the dissociation of ambient gas molecules and the re-deposition of the removed material and leads to higher intensity and longer lifetime of the emission spectra. In SF 6 , a chemical reaction increases the plasma density and weakens the re-deposition effect. The different processes during plasma evolution strongly influence microstructure formation.
Type of Medium:
Online Resource
ISSN:
0263-0346
,
1469-803X
DOI:
10.1017/S0263034613000281
Language:
English
Publisher:
Hindawi Limited
Publication Date:
2013
detail.hit.zdb_id:
2021816-3
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