Plasmonic metasurfaces have been receiving tremendous attention because of their extraordinary optical properties. However, time consuming and expensive fabrication methods such as electron beam lithography or focused ion beam (FIB) hinder its commercial application to sensors, color filters, and photovoltaic solar cells. In this study, we demonstrate that metal-dielectric-metal reflective meta-surfaces can be fabricated in a simple and low-cost way using a one-step covalent bonding-assisted nanotransfer process. We prepared various sizes of nanoscale hole-type patterned silicon master, because the represented color depends on the hole size and period. Ag and SiO2 were deposited onto the replicated polymer stamp from the silicon master, then transferred onto the Al-deposited glass wafer. Strong covalent bonds were formed rapidly between oxygen from the SiO2 and Si from the adhesive. In this way, we easily fabricated metasurfaces using a one-step nanotransfer process. Finally, finite-difference time-domain method (FDTD) simulation was carried out whose outcome matched experimental results, thus verifying our approach.
An etch-less ultraviolet nanoimprint lithography (UV-NIL) process is proposed for patterning a photonic crystal (PC)
structure onto an organic light-emitting diode (OLED) substrate. In a conventional UV-NIL, anisotropic etching is used
to remove the residual layers and to transfer the patterns onto the substrate. The proposed process does not require an
etching process. In the process, a stamp with nano-scale PC patterns is pressed on the dispensed resin and UV light is
then exposed to cure the resin. After tens of seconds, the stamp is separated from the patterned polymer layer on the
substrate. Finally, high-refractive index material is coated onto the layer. The refractive index of the polymer should be
very similar to that of glass. The enhancement of the light extraction was assessed by the three-dimensional (3D) finite
difference time domain (FDTD) method. The OLED was integrated on a nanoimprinted substrate and the electro-luminance
intensity was found to have increased by as much as 50% compared to a conventional device.