Spectroscopic ellipsometer study of correlation of out of plane and in-plane plasmons in silver nanoislands with annealing induced growth

Abstract

In-plane and out of plane plasmons’ study in Ag metallic nanoparticles films deposited onto glass substrate using pulsed laser ablation technique and annealed from 100-400 °C temperature range has been presented using spectroscopic ellipsometer (SE). Effective dielectric constants of nanoislands thin films have been obtained by fitting psi and delta measured from SE which contain the information about annealing induced changes in morphological properties. A simultaneous fitting of p-polarized and s-polarized reflection spectra strengths the uniqueness of applied set of oscillators. Behavior of LSPR peak shift has been discussed in the frame of Modified-Yamguchi model. A shape dependent calculation of plasmon linewidth and further comparison with measured linewidth has been made to predict preferred direction of the annealing induced growth of the film. Morphological facts are also confirmed by FESEM images of the films. Both shifts indicate the dewetting of the film and isolation of nanoparticles. Grain boundary diffusion assisted two-dimensional growth of three dimensional particles is confirmed by present analysis. © 2017 Elsevier Ltd