Highly-regular laser-induced periodic surface structures: Experiment and atomistic modelling

Summary form only given. Surface nano- and microstructuring with additive and subtractive lithography techniques are commonly used in nanotechnology and photonics, while nanoimprint lithography and nanosphere lithography are used for creating periodic structures for plasmonics applications. Single step, maskless optical patterning techniques also exist, notably multi-beam interference based techniques and Laser Induced Periodic Surface Structures (LIPSS). LIPSS have been demonstrated on metals, semiconductors, dielectric surfaces, polymers, and have been used in various applications including solar cells, plasmonics, colorizing metals, wettability and tribology applications. Until recently these optical techniques lacked the long-range periodicity required for some of the applications. Moreover, conventional optical lithography techniques require complex masks, while e-beam lithography and ion-beam lithography require expensive equipment. Recently, a method for direct writing of highly-regular LIPSS (HR-LIPSS) was developed for creating uniform approach overcoming all aforementioned lithography problems [1].In this work, we report the results of a combined experimental and computational study aimed at revealing the mechanisms of HR-LIPSS formation in the ablation regime. Results of a large-scale atomistic simulation performed for a Cr target well agree with experimental observations and reveal the interplay of the material removal and rearrangement in the course of spatially modulated laser ablation leading to the formation of HR-LIPSS. The insights into the mechanisms of the HR-LIPSS formation may help in designing approaches aimed at increasing the processing speed and improving the quality of HR-LIPSS.