Temperature-dependent surface-enhanced
Raman scattering (SERS) is used to investigate the photoluminescence
and background continuum always present in
SERS but whose origin remains controversial. Both the Stokes
and anti-Stokes background is found to be dominated by
inelastic light scattering (ILS) from the electrons in the noble
metal nanostructures supporting the plasmon modes. The anti-
Stokes background is highly temperature dependent and is
shown to be related to the thermal occupation of electronic
states within the metal via a simple model. This suggests new
routes to enhance SERS sensitivities, as well as providing
ubiquitous and calibrated real-time temperature measurements of nanostructures.