(283-290)Nanostructured and nanopatterned gold surfaces: applicationto the surface-enhanced Raman spectroscopy

摘要

Surface-enhanced Raman spectroscopy (SERS)has enormous potential for a range of applications where highsensitivity needs to be combined with good discriminationbetween molecular targets. However, the SERS technique hastrouble finding its industrial development, as was the casewith the surface plasmon resonance technology. The mainreason is the difficulty to produce stable, reproducible, andhighly efficient substrates for quantitative measurements. Inthis paper, we report a method to obtain two-dimensionalregular nanopatterns of gold nanoparticles (AuNPs). Theresulting patterns were evaluated by SERS. Our bottom-upstrategy was divided into two steps: (a) nanopatterning of thesubstrate by e-beam lithography and (b) electrostatic adsorptionof AuNPs on functionalized substrates. This approachenabled us to highlight the optimal conditions to obtain monolayer,rows, or ring of AuNPs, with homogeneous distributionand high density (800 AuNPs/μm2). The nanostructure distributionson the substrates were displayed by scanning electronmicroscopy and atomic force microscopy images. Opticalproperties of our nanostructures were characterized by visibleextinction spectra and by the measured enhancements ofRaman scattering. Finally, we tried to demonstrate experimentallythat, to observe a significant enhancement of SERS, thegold diffusers must be extremely closer. If electron beamlithography is a very attractive technique to performreproducible SERS substrates, the realization of pattern needsa very high resolution, with distances between nanostructuresprobably of less than 20 nm.