SURFACE-ENHANCED RAMAN-SCATTERING AT ELEVATED-TEMPERATURES

The effect on surface-enhanced Raman scattering due to the increase in temperature of the metallic substrate is studied via a simple model f or physisorbed molecules. Surface roughness is represented by a spheri cal or spheroidal island, and the temperature effects on the surface p lasmon are accounted for via a slightly modified Ujihara model. It is found that the enhancement ratio in general decreases as substrate tem perature increases. For noble metals like silver, this temperature eff ect is particularly pronounced at scattering frequencies close to that of the surface-plasmon resonance; and for frequencies well below the surface plasmon frequency, the enhancement ratio is relatively insensi tive to the change of substrate temperature. A tentative explanation i s provided for our modeling results, and the implications from these r esults are discussed.