Measurement of the Distribution of Site Enhancements in Surface-Enhanced Raman Scattering
2008; American Association for the Advancement of Science; Volume: 321; Issue: 5887 Linguagem: Inglês
10.1126/science.1159499
ISSN1095-9203
AutoresYīng Fāng, Nak-Hyun Seong, Dana D. Dlott,
Tópico(s)Nanocluster Synthesis and Applications
ResumoOn nanotextured noble-metal surfaces, surface-enhanced Raman scattering (SERS) is observed, where Raman scattering is enhanced by a factor, G, that is frequently about one million, but underlying the factor G is a broad distribution of local enhancement factors, eta. We have measured this distribution for benzenethiolate molecules on a 330-nanometer silver-coated nanosphere lattice using incident light of wavelength 532 nanometers. A series of laser pulses with increasing electric fields burned away molecules at sites with progressively decreasing electromagnetic enhancement factors. The enhancement distribution P(eta)deta was found to be a power law proportional to (eta)(-1.75), with minimum and maximum values of 2.8 x 10(4) and 4.1 x 10(10), respectively. The hottest sites (eta >10(9)) account for just 63 in 1,000,000 of the total but contribute 24% to the overall SERS intensity.
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