The effect of ambient pressure on laser-induced
silicon plasma temperature, density and morphology

Cowpe, JS; Pilkington, RD; Astin, JS; Hill, AE

Abstract

Laser-induced breakdown spectroscopy of silicon was performed using a nanosecond pulsed
frequency doubled Nd :YAG (532 nm) laser. The temporal evolution of the laser ablation
plumes was characterized under a range of low pressures. Electron densities were determined
from the Stark broadening of the Si (I) 288.16 nm emission line and were found to be in the
range 2.79 × 1016 cm−3 to 5.59 × 1019 cm−3. Excitation temperatures of 9000–21 000K were
calculated using the Si (I) 288.16 nm emission line to continuum ratio. The morphology of the
laser plume, observed with respect to time, was seen to be strongly dependent on the ambient
pressure. The density and temperature of the plasma were also found to vary critically with
plasma morphology. Three ambient pressure regimes were identified where the plasma
evolution was observed to differ markedly. Requirements for the existence of local thermal
equilibrium conditions in the laser-induced plasmas are discussed with respect to these results.

Citation

silicon plasma temperature, density and morphology. Journal of Physics D: Applied Physics, 42, https://doi.org/10.1088/0022-3727/42/16/165202

• Journal Article Type: Article
• Publication Date: Jul 23, 2009
• Deposit Date: Nov 27, 2009
• Publicly Available Date: Apr 5, 2016
• Journal: Journal of Physics D: Applied Physics
• Print ISSN: 0022-3727
• Publisher: IOP Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 42
• DOI: https://doi.org/10.1088/0022-3727/42/16/165202
• Publisher URL: http://dx.doi.org/10.1088/0022-3727/42/16/165202