Processes for Forming Plasmonic Waveguides from Self-Assembled Gold Nanoparticle Thin Films

Abstract

Miniaturization of electronic circuits and systems continue to pose great difficulties in meeting the demand and anticipated growth for information services and their associated electronics. Of the several information processing techniques under consideration for devices of the future, optical systems are considered to offer significant advantages in terms of speed and bandwidth. Unfortunately, at the dimensions of contemporary electronics, optical waveguides will fail to assist significantly due to the fact that standard optical waveguides will have dimensions below the diffraction limit and hence optical waveguiding at such scales will be impractical.

In order to circumvent this, recent work in the area of using nano-sized protrusions to guide light below the diffraction limit has been receiving a decent amount of attention. Such systems have typically involved using electron beam lithography to create these perturbations on metallic surfaces called plasmonic waveguides. While these waveguides are fairly efficient, in the amounts required to make real circuits this method would be impractically slow and prohibitively expensive.

However, such waveguides could be made much more cheaply if means could be found to arrange colloidal nanoparticles on suitable substrates. In this project, nanoscale self-assembly has been investigated with the aim of achieving such ends. Colloidal nanoparticles have been synthesized and self-assembled onto substrates such that they show near field interactions necessary for plasmonic waveguiding without any aggregation. Absorption peak shifts, which were obtained during the experimental phase of this project confirmed that such nanoparticle assemblies can be achieved and that they do demonstrate some plasmonic waveguiding action. With this first step, it is hoped that films like these may find use for quick and cheap plasmonic waveguiding sometime in the near future.