Tuning the surface plasmon resonance and surface-enhanced Raman scattering of pulsed laser deposited silver nanoparticle films by ambience and deposition temperature

Silver nanoparticle (AgNP) thin films were deposited by pulsed laser deposition onto glass substrates, at different fixed temperatures, under inert gas ambience and vacuum. Their morphology, surface plasmon resonance (SPR) and surfaceenhanced Raman scattering (SERS) activities were investigated. AFM analysis of the films showed the formation of densely packed nanoparticles of varying size and shape by changing the ambience and deposition temperature (Ts). A SPR peak is not evidently observed in the spectrum of films deposited at room temperature, in either high vacuum or neon ambience. The SPR frequency blue shifts from 569 to 470 nm and from 581 to 574 nm with increasing Ts for the films processed in high vacuum and in neon ambience, respectively, while the absorption band becomes narrower with increasing Ts. The SERS intensity of Rhodamine B (RhB) adsorbed on a AgNP substrate grown at 600 C in neon ambience exhibits a higher intensity compared with that of RhB adsorbed on the SERS active substrates at other values of Ts. Good correlation has been observed between the SPR and SERS activities and the morphology of the NPs.This study has been partially funded by (i) the Portuguese Foundation for Science and Technology (FCT) under the project PTDC/FIS/098943/2008 and the strategic project PESTC/ FIS/UI0607/2011, and (ii) European COST Actions MP0901NanoTP and MP0903NanoAlloy. The authors KK and KCS are grateful for financial support through the FCT grants SFRH/BPD/87215/2012 and SFRH/BPD/68489/2010 respectively. The authors would also like to thank Engineer José Santos for technical support at the Thin Film Laboratory