Fabrication of nano-gold islands with μm spacing using 2.5 dimensional PDMS stamps

Gold islands with diameters in the range of several tens of nanometers with mu m spacing may act as binding sites for adapter molecules used for single molecule detection using optical fluorescence readout. Microcontact printing (mu CP) using PDMS stamps and alkanethiol chemistry is a straightforward method for the structuring of gold layers. When using binary two dimensional (2D) stamps the softness of the elastomer limits the useable aspect ratio and it was shown that nm-sized features with mu m spacing cannot be replicated with binary PDMS stamps. To bypass this limitation we used 2.5 dimensional PDMS stamps with pyramidal shaped topography to fabricate sub-100 nm gold islands with a spacing of 6 mu m on areas of several square millimeters. The masters, the stamps and the resulting gold structures were analyzed using scanning electron microscopy (SEM). (c) 2008 Elsevier B.V. All rights reserved.