High surface roughness gold nanoparticle/centimeter level silver nanowire heterostructure detectors for SERS application

Abstract

Gold nanoparticle/centimeter level silver nanowire heterostructures were prepared by vacuum thermal evaporation method and solid-state ionics method under 10 μA direct current electric field (DCEF) using fast ionic conductor RbAg4I5 films. The surface morphology and chemical composition of the heterostructures were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. The surface enhanced Raman scattering (SERS) performance was detected by Rhodamine 6 G (R6 G) aqueous solutions as probe molecules. The results indicate that the gold nanoparticle/silver nanowire heterostructures were long-range order and short-range order with the longest length of 2 cm were prepared by vacuum thermal evaporation method and solid-state ionics method. The diameters of the heterostructures ranged from 40 to 90 nm and many regularly arranged gold nanoparticles with the diameter from 5 to 20 nm lie in the prepared heterostructures, which lead to the heterostructures have high surface roughness. The molar ratio of Au:Ag in the heterostructures is 1:19. The limiting concentrations of R6 G for the prepared high surface roughness gold nanoparticle/silver nanowire heterostructures SERS substrates is 10−17 mol/L.