Fabrication of Metallic Nano Pillar Arrays on Substrate by Sputter Coating and Direct Imprinting Processes
In this study, an efficient fabrication process of metallic nanostructures was proposed and the feasibility of the process was verified. This process comprises of direct imprinting and sputter coating techniques. Firstly in this process, a silicon wafer mother mold of nanopattern is prepared by photolithography and dry etching technique. The nanopatterns of mother mold are transferred to an acrylic film by hot embossing method. Secondly, a quartz glass substrate is cleaned in the acetone bath and then by sputter etching for cleaning the contamination on the surface. Then, a substrate is coated with a gold thin film by the Argon gas sputter coating process. Then, an acrylic film mold, whose surface has been patterned with the nanopatterns, is used to transfer directly of pillar pattern onto the gold thin film. As a result, the gold thin films are inflated as nanopillar arrays on the substrate. This is because of the imprinting load from an acrylic film mold is effective to transfer the nanopillar arrays onto a gold thin film. The experimental results show that an acrylic film mold is effective to form the nanopillar arrays on the Au film although the acrylic film mold is softer than Au thin film. Furthermore, the plasmonic properties of the nanopillar arrays are investigated. It is also found that the plasmonic nanopillar arrays show good performance as a localized surface plasmon resonance (LSPR)-active substrate. Feasibility of the proposed process is confirmed by experimental study, and efficiency of the process is discussed.