Promising Substrates for Surface-Enhanced Raman Spectroscopy
Abstract
The goal of this study was to fabricate and characterize metal thin films of silver and
aluminum to determine the effects of deposition thickness and deposition temperature on
nanoparticle morphology and size. Chemical thin films were successfully synthesized by
physical vapor deposition (PVD) onto various substrates. Depositions were accomplished
by either thermal evaporation or electron beam evaporation. A collimator was
implemented that reduced the evaporation spot size of the thermally evaporated copper
phthalacyanine (CuPc). Electron beam deposition of silver and aluminum yielded thin
films that were confirmed with energy-dispersive X-ray spectrometry and X-ray
diffraction. Surface nanostructures were analyzed with scanning electron microscopy
(SEM). A trend of increasing density for silver island clusters with increased deposition
thickness was noted. Increased nanoparticle size for depositions at elevated temperature
was also observed. Similarly, thicker depositions of aluminum yielded larger
nanoparticles and a trend of increased nanoparticle size was observed for elevated
temperature depositions. Further research to characterize and optimize deposition
parameters for surface-enhancement of Raman signals is necessary.