Superiority of localized surface plasmon resonance technique in characterization of ultra-thin metallic films

The comparison and correlation of morphological, optical and crystallographic properties of ultra-thin Au films obtained using field-emission scanning electron microscopy (FESEM), x-ray reflectivity (XRR), UV-visible transmission, and grazing incidence x-ray diffraction (GIXRD) are presented. The Au thin films of different thickness are grown on the glass substrate using the sputtering technique. The particle size, number density and the covered area fraction of Au thin film are obtained from FESEM images. The XRR technique is used to determine the film thickness and surface roughness. The localized surface plasmon resonance (LSPR) response of Au thin films is obtained using UV-Vis transmission spectroscopy. The LSPR peak position and its strength are correlated with film morphology and thickness. Finally, it is shown that LSPR based spectroscopy techniques can provide much better information about morphology and thickness of the Au films up to a resolution of ~1 nm.