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

Laser-Driven One- and Two-Dimensional Subwavelength Periodic Patterning of Thin Films Made of a Metal–Organic MoS2 Precursor

“…Occurring stimulated energy modulations ultimately lead to periodic temperature profiles . As soon as the maximal temperature reached is above what is necessary for material redistribution but still below the decomposition/ablation temperature of the material, hydrodynamic instabilities drive surface-bound material movements leading to stimulus-dependent pattern symmetries. ,,− For a nonablative LIPSS as was demonstrated in this work (Figure ), the material redistribution occurs by thermally driven hydrodynamic instabilities. As hydrodynamic forces, both the Marangoni instability and the Rayleigh–Taylor instability are considered potential driving forces for the material redistribution process .…”

“…It is understood that the repeated laser stimulation of an absorbent solid leads to increased surface roughness, which facilitates the feedback mechanism necessary for LIPSS formation and leads to surface modification. − Roughness-induced scattering waves interfere with the incident laser beam and lead to a periodically modulated energy distribution. , This corresponds to the “Sipe theory”, which predicts sharp adsorption peaks at certain spatial frequencies for dielectric materials with low refractive indices induced by so-called radiation residues originating from certain nonpropagating electromagnetic modes near a rough surface. − As soon as the temperature of the solid enables sufficient molecular dynamics, i.e., above the glass transition temperature ( T g ) for amorphous or the melting temperature ( T m ) for semicrystalline polymer thin films, changes in the surface morphology occur. − Each subsequent laser pulse that interacts with existing surface modulations increases modulation depth and promotes structure refinement. Through scanning a laser spot, the same mechanism drives the pattern proliferation over larger areas. , For linear polarized light, the energy modulation emerges as a one-dimensional pattern periodic parallel to the electric wave field for dielectric solids, ,, whereas for circularly polarized light, the electric vector rotates, leading to a superposition of uniformly distributed wave vectors, resulting in two-dimensional energy modulations. ,, …”

“…Through scanning a laser spot, the same mechanism drives the pattern proliferation over larger areas. 48,49 For linear polarized light, the energy modulation emerges as a onedimensional pattern periodic parallel to the electric wave field for dielectric solids, 32,13,50 whereas for circularly polarized light, the electric vector rotates, leading to a superposition of uniformly distributed wave vectors, resulting in two-dimensional energy modulations. 32,48,51 Occurring stimulated energy modulations ultimately lead to periodic temperature profiles.…”

“…48,49 For linear polarized light, the energy modulation emerges as a onedimensional pattern periodic parallel to the electric wave field for dielectric solids, 32,13,50 whereas for circularly polarized light, the electric vector rotates, leading to a superposition of uniformly distributed wave vectors, resulting in two-dimensional energy modulations. 32,48,51 Occurring stimulated energy modulations ultimately lead to periodic temperature profiles. 52 As soon as the maximal temperature reached is above what is necessary for material redistribution but still below the decomposition/ablation temperature of the material, hydrodynamic instabilities drive surface-bound material movements leading to stimulusdependent pattern symmetries.…”

Self-Aligned Plasmonic Lithography for Maskless Fabrication of Large-Area Long-Range Ordered 2D Nanostructures

“…Most achieved LIPSS are essentially 1D gratings with one of the generally accepted origins from the periodic energy deposition associated with the interference between laser-excited surface plasmon polaritons (SPPs) and incident laser. − Further boosting its diversity into two-dimensional nanostructures was also investigated. Multipath- or multicolor-laser scanning strategies can be used to crisscross carve target samples and form 2D nanopillar arrays; − The periodic energy deposition for ablation can be effectively modulated to fabricate 2D polarization-dependent LIPSS by using a spatially or temporally modulated laser. − Meanwhile, other effects for patterns formation, such as Rayleigh–Plateau hydrodynamic instability and self-organization, can also be employed to couple with the LIPSS formation to create various 2D nanopatterns. − …”