Laser ablation and deposition of aluminium with a specially configured target-substrate arrangement.

The deposition process of Al thin films by nanosecond laser irradiation with a special hemi-cylindrical holder, containing an array of silicon substrates, is studied. The experimental results, obtained by scanning electron microscopy investigation, show that the ablated material produces an unexpected component in a direction that is approximately specular to that of the incident direction of the laser beam. This component, never before reported in the literature, is mainly formed of micrometer droplets. Simple calculations and qualitative assessments show that the forces induced by radiation pressure, thermoelastic waves, or shockwave formation cannot explain the direction of this new component. [ABSTRACT FROM AUTHOR]