C. Douketis et al., ROUGH SILVER FILMS STUDIED BY SURFACE-ENHANCED RAMAN-SPECTROSCOPY ANDLOW-TEMPERATURE SCANNING-TUNNELING-MICROSCOPY, Progress in Surface Science, 50(1-4), 1995, pp. 187-195
The surface topography of Ag films and surface enhanced Raman scatteri
ng (SERS) from benzene on Ag films have been simultaneously recorded.
The Ag films were formed by vacuum deposition at temperatures ranging
from 100 K to 500 K. Analysis of scanning tunnelling microscopy (STM)
images shows that films formed below 250 K are fractal structures with
Hausdorff-Besicovitch dimension 2.55 < D < 2.72, while for those form
ed above 250 K, D approximate to 2. The lower temperature, rough films
exhibit strong surface enhanced Raman scattering but the higher tempe
rature, smooth films do not. We consider the consequences of fractal c
haracter and the possible correlation between this and the SERS activi
ty of these films.