Noble metallic nanostructures exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the scattering cross sections are dramatically enhanced for molecules adsorbed thereon. Thanks to the enorm...Noble metallic nanostructures exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the scattering cross sections are dramatically enhanced for molecules adsorbed thereon. Thanks to the enormously large enhancement factor on the order of 106～10 15, one can readily acquire the vibrational spectra from adsorbates on roughened surfaces of Ag, Au, and Cu. However, SERS has not developed to be as powerful a surface technique as many people had hoped initially because of two specific obstacles. One obstacle is that only three noble metals Au, Ag, and Cu can provide large enhancement, severely limiting the widespread applications involving other metallic materials of both fundamental and practical importance. The other major obstacle is that even for the noble metals, surface morphology with roughness scale of 50～200 nm is crucial to exhibiting a large enhancement factor. The atomically flat surfaces, commonly used in fundamental as well as application research in surface science and nano technology, are not suitable for SERS investigation.展开更多
文摘Noble metallic nanostructures exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the scattering cross sections are dramatically enhanced for molecules adsorbed thereon. Thanks to the enormously large enhancement factor on the order of 106～10 15, one can readily acquire the vibrational spectra from adsorbates on roughened surfaces of Ag, Au, and Cu. However, SERS has not developed to be as powerful a surface technique as many people had hoped initially because of two specific obstacles. One obstacle is that only three noble metals Au, Ag, and Cu can provide large enhancement, severely limiting the widespread applications involving other metallic materials of both fundamental and practical importance. The other major obstacle is that even for the noble metals, surface morphology with roughness scale of 50～200 nm is crucial to exhibiting a large enhancement factor. The atomically flat surfaces, commonly used in fundamental as well as application research in surface science and nano technology, are not suitable for SERS investigation.
