SCANNING FORCE MICROSCOPY STUDY OF METHANOL-INDUCED CHANGES IN THE DISTRIBUTION OF SILVER PARTICLES IN COLLOIDAL METAL-FILMS

Colloidal silver particles were attached to a solid surface for use as a substrate for surface-enhanced Raman scattering and surface enhance d fluorescence spectroscopies. The enhancement of Raman scattering is dramatically increased after exposure of the substrates to methanol so lution. Scanning force microscopy was used to visualize the substrate before and after the methanol treatment, and a statistical evaluation of the particle distribution revealed some differences. The nearest-ne ighbor distance was decreased after the exposure to methanol. This eff ect suggests that an aggregation of the particles occurred. This aggre gation is probably based on increased attractive interactions and late ral mobility of the particles in methanol. (C) 1997 Academic Press