Surface-enhanced Raman scattering active gold nanoparticleanohole arrays fabricated through electron beam lithography

摘要

Graphical abstractDisplay OmittedHighlights•The fabricated gold arrays yielded strong SERS signals under 785nm excitation.•The SERS EFs produced by the nanoparticle arrays were compatible with those of the nanohole arrays.•Nanoparticle aggregation for the nanoparticle arrays could produce stronger SERS enhancement due to LSPR coupling.•The SERS enhancement for the nanohole arrays was attributed to the LSPR wavelength shifting to the near-infrared regime.AbstractEffective surface-enhanced Raman scattering (SERS)-active substrates from gold nanoparticle and gold nanohole arrays were successfully fabricated through electron beam lithography with precise computer-aided control of the unit size and intergap distance. Their SERS performance was evaluated using 4-mercaptobenzoic acid (4-MBA). These gold arrays yielded strong SERS signals under 785 nm laser excitation. The enhancement factors for 4-MBA molecules on the prepared gold nanoparticle and nanohole arrays maxed at 1.08 × 107and 8.61 × 106, respectively. The observed increase in SERS enhancement was attributed to the localized surface plasmon resonance (LSPR) wavelength shifting toward the near-infrared regime when the gold nanohole diameter increased, in agreement with the theoretical prediction in this study. The contribution of LSPR to the Raman enhancement from nanohole arrays deposited on fluorine-doped tin oxide glass was elucidated by comparing SERS and transmission spectra. This simple fabrication procedure, which entails employing electron beam lithography and the controllability of the intergap distance, suggests highly promising uses of nanohole arrays as functional components in sensing and photonic devices.