Continuous-Gradient Plasmonic Nanostructures Fabricated by Evaporation on a Partially Exposed Rotating Substrate

Journal article, 2016

Evaporation on a partially exposed rotating substrate (PERS) was used to generate continuous and precise gradients in nanoscale structure parameters. All materials (gold, chromium, alumina, and silver) were deposited in an electron beam evaporation system with stage rotation and tilt possibilities. All evaporations were performed at a high vacuum. To fabricate nanostructures on a glass substrates by HCL, the substrate was first spin-coated with a layer of 950 PMMA and wetted with a poly(diallyldimethylammonium chloride) (PDDA) solution. Negatively charged PS beads were then drop casted and self-assembled on the surface. A thin layer of metal (gold or chromium) was evaporated to act as a mask. The beads were removed by tape stripping, resulting in a mask with holes arranged in a pattern determined by the colloidal particles. The PMMA situated underneath the holes in the film was removed by oxygen plasma etching. Due to the continuous characteristic of the gradients, high precision in the geometric parameters of fabricated nanostructures can be achieved.