Highly Regular LIPSS on Thin Molybdenum Films: Optimization and Generic Criteria

Our colleagues Juraj Sládek, Kryštof Hlinomaz, Inam Mirza, Yoann Levy, Thibault J.-Y. Derrien, Martin Cimrman and Nadezhda M. Bulgakova, together with Siva S. Nagisetty from Coherent Laser Systems GmbH & Co. KG, Germany, and Jan Čermák, The Ha Stuchlíková and Jiří Stuchlík from the Institute of Physics of the Czech Academy of Sciences, have recently published an article in the MDPI journal of Materials. The topic of the article is Highly Regular LIPSS on Thin Molybdenum Films: Optimization and Generic Criteria.

A systematic experimental study was performed to determine laser irradiation conditions for the large-area fabrication of highly regular laser-induced periodic surface structures (HR-LIPSS) on a 220 nm thick Mo film deposited on fused silica. The LIPSS were fabricated by scanning a linearly polarized, spatially Gaussian laser beam at 1030 nm wavelength and 1.4 ps pulse duration over the sample surface at 1 kHz repetition rate. Scanning electron microscope images of the produced structures were analyzed using the criterion of the dispersion of the LIPSS orientation angle (DLOA). Favorable conditions, in terms of laser fluence and beam scanning overlaps, were identified for achieving DLOA values <10°. To gain insight into the material behavior under these irradiation conditions, a theoretical analysis of the film heating was performed, and surface plasmon polariton excitation is discussed. A possible effect of the film dewetting from the dielectric substrate is deliberated. Read the full article.