High surface-enhanced Raman scattering activity from Au-decorated individual and branched tin oxide nanowires

Abstract

Individual tin oxide (SnO2) nanowire and three-dimensional (3D) branched SnO2 nanowires decorated with Au nanoparticles are investigated as the substrates for surface-enhanced Raman scattering (SERS) application. Rhodamine B, isothiocyanate with a concentration of 1.0 μM/l can be easily detected due to the localized surface plasmon resonance of the Au nanoparticles on the SnO2 nanowire. The SERS enhancement factors of the individual Au-coated nanowire and 3D branched SnO2 nanowires are estimated to be 1.1×107 and 1.0×107, respectively. The high SERS activity of the 3D branched SnO2 nanowires is due to the plentiful Au droplets and the formation of lots of “hot spots” in regions between adjacent Au droplets on tips of the branches.