Experimental Evidence of Particles due to Thermal Effects in Laser Ablation

Thermal effects on the target surface, promoted by laser-target interaction, include boiling, vaporization and mainly phase explosion, play an important role in the surface morphological modification of the target, which in turn, originate morphological modification of the film. This article describes the phenomenology of these thermal effects when YBa2Cu3O7- films are grown by Pulse Laser Deposition. The surface morphological modification of the target includes elongated hemispherical particles in a range from 1 µm to 7 µm, cones, folds and regions that show melting processes with subsequent resolidification. YBa2Cu3O7- films exhibit spherical particles from 0.4 µm to 6 µm, terraces, bumps, and porosity. Applications in micro and nanotechnologies are limited by this film morphology. YBa2Cu3O7- films have been grown on electrolytic copper. The surface morphology of targets and films is studied by scanning electron microscopy. The results show that the thermal effects are decisive in morphology modification and surface stoichiometric film composition.