Rapid thermal annealing is an advantageous method for preparation of plasmonic nanostructures, which offers low cost and controllable size and geometry. The mechanism of nanoparticles evolving with holding time via rapid thermal annealing is significant for turning plasmonic effect of nanostructures. In this work, the morphology evolution of silver nanoparticles on quartz substrate (AgNPs / SiO2)under different holding time was studied. The size and geometry of AgNPs were characterized by using the field emission scanning electron microcopy and by using statistical method. It is found that when holding time was 15 s, the continuous silver film transformed into uniform Ag islands and secondary nanoparticles with respective mean size of (152±46)nm and (53±13)nm. This is attributed to that AgNPs inherit the morphology features of original defects produced during silver film sputtering. After annealing, the channel networks in the continuous silver film diffusely shrink to strip islands. The secondary nucleuses originally grew in the channel network turn into small nanoparticles, which are called the secondary nanoparticles. When the holding time increases from 15 s to 1 min and 5 min, the strip islands change into spherical crown particles with size decreased and quantity unchanged. When annealed for 10 min, the number of secondary nanoparticles substantially drops resulting from the evaporation during the ripening process. It is found that AgNPs annealed for 5 min exhibits significant plasmonic effect in the surface enhanced Raman scattering measurement of crystal violet molecules, with content as low as 10-8 mol / L. It reveals that the geometry and size of AgNPs can be turned via regulating the holding time, providing a theoretical base for preparation of plasmonic substrate by rapid thermal annealing. It also helps for applications of plasmonic nanostructures into solar cells and trace detection. © 2023 Cailiao Daobaoshe/Materials Review. All rights reserved.
