In-situ monitoring and characterization of Nanoparticles During W Ablation in N2 Atmosphere
2003 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 94, no 3, 2011- p.Article in journal (Refereed) Published
ABSTRACT Nanoparticles were generated by pulsed laser ablation of tungsten in a N[sub 2] ambient at atmospheric pressure. Size distributions and concentrations were monitored in situ versus laser fluence, repetition rate, and ablated spot size, by a differential mobility analyzer and a particle counter. The multishot ablation threshold was determined to be ∼6 J/cm² for the laser used (ArF excimer, δ = 193 nm). Mostly small, nonlognormally, distributed particles (<20 nm in diameter) were generated below the ablation threshold (Φ[sub th]), and the relative concentration of larger particulates (>20 nm in diameter) increased above Φ[sub th]. Modeling of the temperature and ablated depth dependence on fluence showed that the formation of clusters below Φ[sub th] could not be assigned to a thermal process, but are connected to particle condensation from a photochemically desorbed thin layer. X-ray diffraction and x-ray photoelectron spectroscopy analysis performed on polydisperse nanoparticles revealed an amorphous phase of the particles, and the elemental composition was found to be WN[sub 0.3].
Place, publisher, year, edition, pages
2003. Vol. 94, no 3, 2011- p.
IdentifiersURN: urn:nbn:se:uu:diva-90508DOI: 10.1063/1.1587253OAI: oai:DiVA.org:uu-90508DiVA: diva2:162883