title: Nanosphere arrays with controlled sub-10-nm gaps as surface-enhanced raman spectroscopy substrates.
abstract: We demonstrate a convenient and cost-effective chemical approach for fabricating highly ordered Au nanoparticle arrays with sub-10-nm interparticle gaps. Near-field enhancements inside the interparticle gaps create uniform periodic arrays of well-defined "hot spots" exploitable for large surface-enhanced Raman spectroscopy (SERS) enhancements. A cetyltrimethylammonium bromide (CTAB) bilayer surrounding each individual nanoparticle upon array crystallization is responsible for this periodic gap structure; displacement of the CTAB by smaller thiolated molecules does not affect the structural integrity of the arrays. As SERS substrates, the as-fabricated Au nanoparticle arrays exhibit high SERS sensitivity, long-term stability, and consistent reproducibility.
authors.affiliation: Department of Chemistry, Rice University, Houston, Texas 77005, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: Carly S
authors.initials: CS
authors.lastname: Levin
authors.forename: Naomi J
authors.initials: NJ
authors.lastname: Halas