[24p-E106-1~18] 3.7 Laser processing

▲ [24p-E106-8] Control of LIPSS Geometries on ZnO Substrates by Ultrafast Laser with Different Conditions

〇(P)Shi Bai¹, Kotaro Obata¹, Koji Sugioka¹ (1.RAP, RIKEN)

Keywords:femtosecond laser, laser processing, nanostructure

Irradiation of ultrafast laser with laser fluence near the ablation threshold creates unique 1-dimensional (1D) or 2D periodic nanostructures on surfaces of various materials, including metals, semiconductors and dielectric materials, which is called laser-induced periodic surface structures (LIPSS). LIPSS have been considered for the applications to wettability control, sensor, surface coloring, etc. [1-3]. In this presentation, we present our recent research on the fabrication of periodic nanostructures on single crystal zinc oxide substrates by ultrafast laser. Specifically, we demonstrated the influence of laser processing parameters, including laser fluence, wavelength, scanning speed, pulse width, and polarization on morphologies of the formed periodic structures. The formation mechanism of periodic structures is briefly discussed based on the current theories of electromagnetic and matter reorganization models. By optimizing the laser processing parameters, the nanogrooves and nanogaps with a width narrower than 20 nm can be fabricated. The linearly polarized beam generates typical 1D LIPSS which is a nanostripe array. We have further found that the circularly polarized beam creates a nanodot array (2D LIPSS) as shown in Figure 1. We expect our experimental results are beneficial for the understanding of LIPSS formation mechanism and open up a new pathway for surface texturing by laser processing.
References:
[1] C Florian et al. ACS Appl. Mater. Interfaces 2018, 10, 36564−365711
[2] S Bai et al. ACS Appl. Mater. Interfaces 2020, 12, 42328−42338
[3] J Huang et al. Nanophotonics 2019, 8, 869-878