Fabrication of the Au Nano-Aperture Array Platform for Single Molecule Analysis

Abstract

We have fabricated the Au nano-aperture array platforms on the Au films for single molecule analysis. Previously, we reported fabrication of the 200 nm wide double slits with various separations between two nanoslits, and the optical characteristics. In this paper, we will address the optical characteristics of various Au aperture platfoms; the double slits with a 50 nm opening width, the nanoslit array with its opening width less than 100 nm, and the circular type nano-aperture by using 30 keV focused Ga ion beam techniques, along with Au nanopore formation under the high energy electron beam irradiations at 200 keV. For the slit width less than 100 nm, we observed the surface plasmon polariton (SPP)-mediated intraband transmission peak at ∼500 nm, and the SPP-coupled peak around ∼650 nm. The optical intensities are measured to be dependent upon the size of the nano-aperture, the opening width of the slit, and the thickness of the Au film. For a 30 nm slit width, the broadband emission ranging from ∼600 nm to 800 nm were also observed. The fabricated Au plasmonic platforms can be utilized as single molecule bio-sensor.