文摘
Aligned Ag nanorod arrays have been fabricated on glass substrates using an oblique angle vapor deposition(OAD) method. The surface morphology and structure of the Ag rods were studied by scanning electronmicroscopy, transmission electron microscopy, and X-ray diffraction. Individual nanorods were found to beprimarily cylindrical, albeit with irregularly shaped surface protrusions of the rods. The surface enhancedRaman scattering (SERS) response as a function of nanorod length was investigated using trans-1,2-bis(4-pyridyl)ethene as a probe molecule at an excitation wavelength of 785 nm. The enhancement factors reacheda maximum of ~5 × 108 as the nanorod length approached 868 nm and then decreased to ~3 × 106 as thenanorod length increased further to 1900 nm. For the 868 nm nanorod array, signals collected over multiplespots within the same substrate resulted in a relative standard deviation (RSD) of 10%, while an RSD of 15%was measured in signals collected from different substrates. When stored in a food vacuum bag, the substratesare stable with respect to SERS intensity for greater than 2 months. This study demonstrates that the OADAg nanorod arrays are highly sensitive, uniform, and stable SERS substrates that are suitable for a variety ofsurface chemical analysis applications.