Evidence of liquid phase during laser-induced periodic surface structures formation induced by accumulative ultraviolet picosecond laser beam
- ICMN, UMR 7374, CNRS/University of Orleans, 1b rue de la Ferollerie, CS 40059, 45071 Orleans Cedex (France)
- CME, UFR Sciences, University of Orleans, 1 Rue de Chartres, BP 6759, 45067 Orleans Cedex 2 (France)
Laser-induced periodic surface structures (LIPSS) were formed on Cu/Si or Cu/glass thin films using Nd:YAG laser beam (40 ps, 10 Hz, and 30 mJ/cm{sup 2}). The study of ablation threshold is always achieved over melting when the variation of the number of pulses increases from 1 to 1000. But the incubation effect is leading to reduce the threshold of melting as increasing the number of laser pulse. Also, real time reflectivity signals exhibit typical behavior to stress the formation of a liquid phase during the laser-processing regime and helps to determine the threshold of soft ablation. Atomic Force Microscopy (AFM) analyses have shown the topology of the micro-crater containing regular spikes with different height. Transmission Electron Microscopy (TEM) allows finally to show three distinguished zones in the close region of isolated protrusions. The central zone is a typical crystallized area of few nanometers surrounded by a mixed poly-crystalline and amorphous area. Finally, in the region far from the protrusion zone, Cu film shows an amorphous structure. The real time reflectivity, AFM, and HR-TEM analyses evidence the formation of a liquid phase during the LIPSS formation in the picosecond regime.
- OSTI ID:
- 22486060
- Journal Information:
- Applied Physics Letters, Vol. 107, Issue 19; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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