The SERS Effect as a Tool for Studying Molecules Adsorbed on Semiconductor Surfaces

We have demonstrated that adsorbed species on semiconductor surfaces can be detected by SERS spectroscopy by using two SERS-activation procedures. One consists of depositing on the semiconductor surface an Ag island film, the other based on the use of a chemical etching process. The observed SERS spectra of the adsorbed molecules are similar in both SERS-activation procedures. No Raman scattering could be detected from the GaAs surface without either the etching procedure or the Ag film because the vibrational spectra of molecules adsorbed on semiconductor surfaces were too weak to be detectable without an enhanced Raman cross section. These results are important from the SERS point of view because they show that semiconductors are capable of supporting the SERS effect.