Jing Tang et al 2008 Nanotechnology 19 415702 doi:10.1088/0957-4484/19/41/415702
Jing Tang1, Ekaterina V Ponizovskaya, Alexander M Bratkovsky, Duncan R Stewart, Zhiyong Li1 and R Stanley Williams
Show affiliationsWe studied the effect of the substrate on the surface-enhanced Raman scattering (SERS) signals of metallic nanocrystal films by making a direct comparison between cases with metallic and semiconducting substrate surfaces. Ag nanoparticles smaller than 10 nm were synthesized and uniform arrays were formed on both ultrasmooth metallic and Si surfaces. These substrates provide reproducible SERS signals with high enhancement factors over large areas. Moreover, a SERS signal about one order of magnitude higher was obtained in the metallic surface case as compared with the Si substrate case, which is attributed to stronger plasmon coupling between the nanoparticles and their charge-conjugate images in the underlying metallic surface. The interpretation of our experimental results was confirmed by our finite difference time domain calculations. The dependence of the interaction between the nanoparticles and the substrate surface on the direction of the incident electromagnetic field is also discussed.
78.30.Er Solid metals and alloys
78.66.Bz Metals and metallic alloys
Condensed matter: electrical, magnetic and optical
Issue 41 (15 October 2008)
Received 7 May 2008, in final form 19 June 2008
Published 4 September 2008
Jing Tang et al 2008 Nanotechnology 19 415702
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