Raman Spectrometry of Scattering of Nano-Gold Ceria Films

Abstract

Gold nano-particles (NPs) were sputtered onto spin-coated ceria film, and different Au NPs concentration were achieved by varying the deposition time; at 90 s (90Au–CeO2) and 120 s (120Au–CeO2). The nano-gold ceria film was exposed to a low power laser irradiation (10 mW) at 532 nm to produce localized surface plasmons resonance (LSPR). The LSPR from the gold NPs causes the magnification of the F2g Raman mode of ceria through surface-enhanced Raman scattering (SERS), and induced crystals anharmonicity caused by plasmon heating. The Raman intensities of ceria for 90Au–CeO2 and 120Au–CeO2 were almost similar, however, the redshift and full-width at half maximum (FWHM) of the ceria F2g Raman mode were greater for 90Au–CeO2 This was due to the gaps present between the gold NPs, which contribute to the enhancement of electrical field intensity distribution. In the case of 120Au–CeO2, the electrical field enhancement was reduced because of the inter-NP gaps were reduced with the increase in concentration of the gold NPs. The finite element method (FEM) was used to demonstrate the effect of the inter-NP gaps on the electrical field intensity distribution.