Generation of 2D-arrays of anisotropically shaped nanoparticles by nanosecond laser-induced periodic surface patterning

Abstract

Two-dimensional surface pattern formation is achieved by irradiation of a gold thin film on a silicon wafer by circular- or non-polarized nanosecond laser pulses. It is shown that the laser-induced reorganization may be described by the same principles as laser-induced periodic surface structure (LIPPS) formation using linear polarized light, which generates typical stripe-like patterns. The 2D-process shows some astonishing similarities with a simple interference feedback loop modeling material redeposition. The periodicity Λ of the created hexagonal and square patterns is in good agreement with calculations of the theoretically calculated wavelength of surface plasmon polaritons (SPPs). The morphology of the created nanoparticles is analyzed with focused ion beam scanning electron microscopy (FIB-SEM), revealing the dependence on the substrate’s crystallographic orientation. Generated patterns may be either converted into ‘nanohole’ arrays or used for the synthesis of exotically shaped and highly uniform gold nanoparticles.