Posted: September 24, 2007

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(Nanowerk News) Metallic nanostructures are recently attracting increasing interest for their plasmonic properties, offering a great potential for sensing, spectroscopic, or nano-optical applications. In order to tap into the full potential of plasmonic nanostructures, however, techniques that allow for accurate control of their (3D) shape and position need to be developed.
Researchers at the ICFO in Barcelona (Spain) have recently shown that electron-beam induced deposition (EBID) can be successfully used to create plasmonic nanoscale gold structures with accurate shape and position control (also see our Nanowerk Spotlight "Plasmonics and optical tweezers - nanotechnology that manipulates with light".
Although EBID has been known for some year as a maskless lithography tool with potential for the creation of nanoscale structures, so far it was impossible to achieve sufficient material purity and thus plasmonic effects and applications were out of reach.
Plasmonic gold needles
Plasmonic gold needles grown with EBID on a titanium coated (4 nm) glass surface (45° tilt SEM image). (Image: Dr. Quidant, IFCO)
In the work recently published by Graells et al. ("Growth of plasmonic gold nanostructures by electron beam induced deposition"), the ICFO team achieves high aspect-ratio gold structures that exhibit plasmonic properties. The technique they propose opens new perspectives in the fabrication of substantial height-base aspect ratio plasmonic nanostructures impossible to fabricate otherwise with conventional e-beam lithography. It may become particularly relevant for non-flat substrates and overcomes the main limitations of other nanostructuring techniques like lift-off.
The ICFO-Institute of Photonic Sciences is a nonprofit agency founded in 2002 in Barcelona that aims at advancing the limits of scientific and technological knowledge in optical sciences including quantum optics, nonlinear optics, bio-photonics and nano-optics. ICFO hosts 15 research groups that use some 45 laboratories and one nanophotonics fabrication facility in a 9000 sq.m. dedicated building. The centre is engaged in both, research and education and training of M.S.c and Ph.D. students and post-doctoral researchers. Also, ICFO collaborates actively with many leading European research centers and Universities, as well as with leading institutes worldwide.
Source: ICFO