Engineering Plasmonic Lattice Structures for Lab-on-Chip Biosensing Platforms

Abstract

The fabrication of plasmonic devices has often relied on low-throughput sub-micron to nanoscale fabrication techniques, making the production of transducers for experimentation and implementation as lab-on-chip components challenging. This paper aims to improve on those challenges, and discusses the design and fabrication of nanosphere-based plasmonic lattices that directly utilize nanosphere deposition to create resonant plasmonic transducers that operate in the visible spectrum. Parametric simulation of critical plasmonic lattice dimensions using finite-difference time-domain (FDTD) software to determine maximum electric field (E-field) enhancement for a range of commercially-available silica nanobeads are presented. An evaporative process that achieves fabrication of a sub-micron lattice consisting of a self-assembled monolayer of silica nanobeads sized in the 100 nm range is described, along with an evaluation of fabrication tolerance compared to as-drawn geometries used in simulations. Characterization results indicating greater than 300-fold enhancement of photonic emission from suspended labeled analytes is also presented.