Laser ablation of a Cu–Al–Ni combinatorial thin film library: analysis of crater morphology and geometry

• DOI: 10.1007/s00339-016-0608-4
• Publication Date: 2016-12-05T00:21:00Z
• Authors: Simina Aurelia Re...; Keith Thomas; Vipin Chawla; Johann Michler; Ming Chu Kong
• Keywords: Laser Ablation

The conventional approach to studying laser–workpiece interaction in the ablation regime is to vary beam parameters used on a specimen of uniform chemical composition. The current work instead utilises a pulsed laser beam of constant parameters to ablate a ternary alloy thin film where the chemical composition of the sample varies continuously; this will enhance the understanding of pulsed laser ablation by means of a combinatorial approach. The analysis of the studied workpiece (a Cu–Al–Ni thin film deposited by magnetron sputtering) revealed the presence of both compositional and morphological gradients. Variation in the surface morphology was correlated with aluminium content. Single-pulse laser ablation (Nd:YAG, 1064 nm, 30 ns, 4.54 J/cm2) of the surface resulted in different crater features, geometry and volume. Two characteristic regions separated by a transition zone were identified based on the craters’ geometrical and morphological characteristics. The ablated volume increases with the atomic percentage of aluminium up to a threshold value of roughly 30 at.% after which the ablation volume slowly declines. This phenomenon may be attributed to plasma absorption and heat dissipation in the thin film.