Raman scattering from nanocrystalline Ag compacted under different pressures

Nanocrystalline silver samples compacted under different pressures have been studied by X-ray diffraction and Raman spectroscopy. X-ray photoelectron spectroscopy results of the polished nanocrystalline silver samples suggest the formation of silver dioxide at the interfaces. Raman spectra of the as-polished nanocrystalline silver samples exhibit a weak band at about 240 cm, which can be attributed to surface-enhanced bands originating from the silver dioxide dispersed at the surface of the silver grains. When the compacting pressure is increased, the intensity of the Raman peak at about 240 cm decreases due to decreasing silver dioxide in the interfaces. Also, the peak exhibits a frequency shift upwards which has been attributed to a molecular contraction, i.e. residual stress developed during the pressing of the powders. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.