Nanoparticle generation and transport resulting from femtosecond laser ablation of ultrathin metal films: Time-resolved measurements and molecular dynamics simulations

Journal Article · Mon May 12 04:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4876601· OSTI ID:22273403

Puretzky, A. A.; Geohegan, D. B. ^[1]; Shih, C. -Y.; Wu, C.; Zhigilei, L. V. ^[2]

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1. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2. Department of Materials Science and Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)

The synthesis of metal nanoparticles by ultrafast laser ablation of nanometers-thick metal films has been studied experimentally and computationally. Near-threshold backside laser ablation of 2–20 nm-thick Pt films deposited on fused silica substrates was found to produce nanoparticles with size distributions that were bimodal for the thicker films, but collapsed into a single mode distribution for the thinnest film. Time-resolved imaging of blackbody emission from the Pt nanoparticles was used to reveal the nanoparticle propagation dynamics and estimate their temperatures. The observed nanoparticle plume was compact and highly forward-directed with a well-defined collective velocity that permitted multiple rebounds with substrates to be revealed. Large-scale molecular dynamics simulations were used to understand the evolution of compressive and tensile stresses in the thicker melted liquid films that lead to their breakup and ejection of two groups of nanoparticles with different velocity and size distributions. Ultrafast laser irradiation of ultrathin (few nm) metal films avoids the splitting of the film and appears to be a method well-suited to cleanly synthesize and deposit nanoparticles from semitransparent thin film targets in highly directed beams.

• OSTI ID: 22273403
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 19 Vol. 104; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
LASER RADIATION
LASERS
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
PARTICLES
SUBSTRATES
THIN FILMS
TIME RESOLUTION