Effects of Morphology of Nanodots on Localized Surface Plasmon Resonance Property

Abstract

In this paper, authors report the effects of process parameters of thermal annealing method on the morphology and Localized Surface Plasmon Resonance (LSPR) property of gold nanodots. Results show that the nanodots aggregated on a quartz glass substrate are large and sparse, while the nanodots aggregated on a silicon substrate are small and dense. The peak of the absorbance spectra is shifted to a longer wavelength and becomes broader when the gold film is thicker. The absorbance intensity increases with the increase in the gold film thickness. Increase the annealing temperature and/or the annealing time result in a blue shift of the absorbance peak and a decrease in the peak intensity. It is found that the variation in the absorbance peak wavelength and peak intensity closely correlates to the variation in the average circularity of the nanodots. This result suggests that the LSPR of nanodots can be tuned by controlling the morphology, specifically the circularity, of the nanodots.