Fabrication of hemispherical cavity arrays on silicon substrates using laser-assisted nanoimprinting of self-assembled particles

A new approach to fabricating hemispherical cavity arrays on silicon (Si) substrate using laser-assisted nanoimprinting of self-assembled particles is presented. A monolayer of silica particles, with different diameters of 0.30 and 0.97 µm, was deposited on a Si substrate by self-assembly. A quartz plate was tightly placed on the sample surface to firmly sandwich the self-assembled nanoparticle monolayer. The silica particles were imprinted into Si substrates after laser irradiation (KrF excimer laser, λ = 248 nm) on the quartz/nanoparticle/Si structure with a single pulse. Ultrasonic cleaning and hydrofluoric acid (HF) solution were used to remove the silica particles in the sample surface. Hemispherical cavities were formed on the substrate surface. The influence of laser fluence and particle size on the structuring of the surface has been investigated. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were performed to observe the dimensions of the cavities. One-dimensional thermal calculation was employed to calculate the thermal effects in this process.