ABSTRACT
Raman spectroscopy is based on vibrational transitions that yield very narrow spectral features charac-
teristic of the investigated samples. Thus, it has long been considered as a valuable tool for the
identification of chemical and biological samples as well as the elucidation of molecular structures,
surface processes, and interface reactions. Despite these important advantages, Raman scattering appli-
cations are often limited by the extremely poor efficiency of the scattering process. However, discoveries
in the late 1970s indicated that the Raman scattering efficiency can be enhanced by factors of up to
106 when the sample is adsorbed on or near nano-textured surfaces of special metals such as silver, gold,
and transition metals. The technique associated with this phenomenon is known as surface-enhanced
Raman scattering (SERS) spectroscopy. The use of Raman and SERS spectroscopies for the detection of
hazardous chemicals, such as environmental pollutants, explosives, and chemical warfare agents or simu-
lants, has been reviewed [1,2]. Since Raman spectroscopy is nondestructive and highly compound-specific,
the potential to spectrally analyze multicomponent samples is the primary advantage of Raman and
SERS over fluorescence-based detection [3-22]. This is mostly due to the presence of much narrower
spectral bands, which allows structural identification and conceivably simultaneous measurement of
different analytes in complex samples.
