Nano-hole Arrays in Thin Au/Pd Film on Glass, for High Speed Molecular Analysis

We present an improved process technology based on e-beam lithography and lift-off technique, for fabrication of different nano-hole arrays in optically thick gold/palladium (Au/Pd=60/40) layers on transparent substrates. Every hole serves as a reaction chamber for bio-molecular analysis (e.g. antibody/antigen recognition), as part of a novel atto-liter titer plate device. The optical characterization of the hole-arrays is pursued, both for the transmission of the light and the fluorescence signal through the holes. Array structures with square and hexagonal holes' distribution, with the hole-diameters between 150 nm and 200 nm and periodicity of 600 nm and 900 nm are fabricated in 200 nm thick layer of gold/palladium alloy on glass. The spectrum of the transmitted light through the hexagonally distributed nano-holes compared to the one of the square distributed nano-holes shows a 20% of light enhancement. Applying Rhodamine G6 solution (0.05 mM) on top of the arrays reveals a nine time increased fluorescent signal.