Probing innovative microfabricated substrates for their reproducible SERS activity.

New types of microfabricated surface-enhanced Raman spectroscopy (SERS) active substrates produced by electron beam lithography and ion beam etching are introduced. In order to achieve large enhancement factors by using the lightning rod effect, we prepare arrays consisting of sharp-edged nanostructures instead of the commonly used dots. Two experimental methods are used for fabrication: a one-stage process, leading to gold nanostar arrays and a two-stage process, leading to gold nanodiamond arrays. Our preparation process guarantees high reproducibility. The substrates contain a number of arrays for practical applications, each 200x200 microm2 in size. To test the SERS activity of these nanostar and nanodiamond arrays, a monolayer of the dye crystal violet is used. Enhancement factors are estimated to be at least 130 for the nanodiamond and 310 for the nanostar arrays.