Laser-assisted nanoimprinting of self-assembled single size and binary-size nanoparticles on silicon and aluminum substrates

A monolayer of self-assembled silica particles can be imprinted into a silicon (Si) substrate by laser irradiation (KrF excimer laser, λ=248 nm). Periodical hemispherical cavities can be therefore created on the substrate surface. The influences of various particle sizes and laser fluence were investigated. In addition, preheating of the substrate significantly improves the performance. One-dimensional thermal calculation was employed to understand the thermal effects in this process. Three-dimensional optical simulation provided an accurate insight into the light intensity enhancement. Raman spectroscopy was used to examine the stress induced by the laser imprinting process resided in the cavity structures. Self-assembly of binary-size nanoparticles was achieved and its application on the fabrication of binary-size nanocavity arrays by laser-assisted nanoimprinting was investigated.