Surface-enhanced Raman scattering effects of gold nanorods prepared by polycarbonate membranes

Using a polycarbonate membrane (PCM) as a template, and combining with the electrochemical deposition method, we prepare gold nanorods each with about 36 nm in diameter and 1 mu m in length. We measure transmission spectra, and find that the resonant absorption peak is at around 540 nm. Subsequently, the enhancement effects of the nanorods are investigated with 514 nm and 633 nm laser excitations. Comparing the spectra under resonant condition with those under non-resonant condition, we conclude that the field enhancement effect under the resonant excitation is more prominent than under the non-resonant excitation. The enhancement factor under the resonant excitation is increased to 7 times of the factor under the non-resonant excitation. Comparing with similar researches, we achieve the following two improvements: 1) with a resonant excitation, we significantly increase the enhancement factor of gold nanorods; 2) we eliminate the fluorescence of PCM molecules, thus make the template method more feasible for transparent surface-enhanced Raman scattering substrate applications.