Influence of metal grain size on surface-enhanced Raman scattering

Journal Article · Sun Sep 15 00:00:00 EDT 1991 · Physical Review, B: Condensed Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.44.6372· OSTI ID:5190022

XDawson, P ^[1]; Alexander, K B; Thompson, J R; Haas, III, J W; Ferrell, T L ^[2]

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1. Department of Pure and Applied Physics, Queen's University, Belfast BT7 1NN (United Kingdom)
2. Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee (USA)

The surface roughness of nominally smooth and of randomly roughened thin silver films is characterized using scanning tunneling microscopy and the metal grain size is assessed using transmission electron microscopy. On each type of substrate used, glass or CaF{sub 2}-roughened glass, the silver films are deposited either very slowly ({similar to}0.15 nm s{sup {minus}1}) or quite quickly ({similar to}2.0 nm s{sup {minus}1}). Only silver films deposited on CaF{sub 2}-roughened glass yield measurable surface-enhanced Raman signals for benzoic acid; the enhancement is brought about by surface field amplification due to the excitation of delocalized surface-plasmon polaritons. However, the surface-enhanced Raman signals obtained from the slow-deposited silver films are significantly better (by about a factor of 3) than those obtained from the fast-deposited silver films on a given CaF{sub 2}-roughened substrate. The explanation of this observation does not lie with different surface roughness; both types of film yield closely similar data on the scanning tunneling microscope. Rather, it is suggested that the relatively small grain size of the fast-deposited silver films leads to increased elastic scattering of surface-plasmon polaritons at the grain boundaries, with a consequent increase of internal damping. This results in a reduction of the scattered Raman signal.

• OSTI ID: 5190022
• Journal Information: Physical Review, B: Condensed Matter; (United States), Vol. 44:12; ISSN 0163-1829
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILVER
RAMAN SPECTRA
THIN FILMS
GRAIN BOUNDARIES
GRAIN SIZE
ROUGHNESS
SCANNING ELECTRON MICROSCOPY
SUBSTRATES
TRANSMISSION ELECTRON MICROSCOPY
CRYSTAL STRUCTURE
ELECTRON MICROSCOPY
ELEMENTS
FILMS
METALS
MICROSCOPY
MICROSTRUCTURE
SIZE
SPECTRA
SURFACE PROPERTIES
TRANSITION ELEMENTS
360602* - Other Materials- Structure & Phase Studies