Large-area

X. Chen, K. Jiang
Micro Engineering and Nanotechnology Group, Department of Mechanical Engineering, University of Birmingham, B15 2TT, UK

Abstract

Many of current techniques are not suitable for the fabrication of metallic nanostructure on the scale of usual optical coatings at reasonable fabrication cost and time. A fabrication process for producing large-area metalcoated periodic nanopillars is presented. A hybrid metallic nanostructure array was obtained by depositing a silver film with a thickness of ~40 nm on the fused silica nanopillars with an in-plane diameter of ~140 nm and out-ofplane height of ~130 nm, which was fabricated by a combination of interference lithography, metal deposition and etching. There are two peaks in the extinction spectrum of the p-polarized incident light, one at 585.3 nm and the other 493.6 nm. The shift of the higher peak is 32.9 nm (a red-shift), while that of the lower peak is 42.3 nm (a blue-shift) with the addition of absolute ethanol on the sample surface. Such structure was used to monitor the evaporation process of the absolute ethanol on the sample surface. It was found that narrowest extinction peak appears at normal incidence, while the polarization of the incident light does not affect the experimental result due to the symmetrical distribution of the nanostructures. The fabrication process and unique optical properties of the structure array are expected to be suitable for the development of high-throughput ultrasensitive chemical sensor arrays.