Effects of static and dynamic femtosecond laser modifications of Ti/Zr multilayer thin films

Abstract

The experimental study of the static and dynamic femtosecond laser ablation of the multilayer 15x(Ti/Zr)/Si system is reported. The layer-by-layer selective laser ablation mechanism was studied by analysis of the surface morphology and elemental composition in static single pulse irradiation in a range of pulse energy from 10 to 17 $$\upmu $$ μ J. The selective ablations, as number of concentric circles in modified spots are increased with the pulse energy. The boundary between the circles was shown a change in the depth, comparable to the thickness of the individual layers. Changes in the elemental composition at the edges are associated with the removal of the layer by layer. The dynamic multipulse irradiation was observed via the production of lines with laser-induced periodic surface structures (LIPSS) at different laser parameters (scan velocities and laser polarization). The spatial periodicity of the formed LIPSS depends on changes in the effective number of pulses and laser polarization, as well as the nature of the material. For better interpretation of the experimental results, simulations have been conducted to explore the thermal response of the multiple layered structure 15x(Ti/Zr) after static single pulse irradiation. Graphic Abstract

Cell Response on Laser-Patterned Ti/Zr/Ti and Ti/Cu/Ti Multilayer Systems

“…The results indicate that oxygen from the atmosphere more readily oxidized the surface where copper was present. Taking into account the current and previous studies of a similar Ti/Zr multilayer system, it can be concluded that a larger fraction of the laser pulse energy delivered to the system induces intense ablation (removal of between 100 and 200 nm thin film), while a smaller fraction of the absorbed energy induces changes in the composition, coinciding with a change in the lattice temperature (in-depth about 50 nm) based on the numerical simulation of the temperature profile [36,46,47]. Surface free energy (SFE) can be considered a quantity that characterizes the affinity of a surface for other materials (e.g., liquids).…”