This article reports on a project that observed enhanced Raman intensity of the phonon modes of nanosized semiconductor particles induced by adsorption of various molecules.
This is in contradistinction to surface-enhanced Raman spectroscopy (SERS), in which the Raman lines of an adsorbate are enhanced by proximity to either a metal or semiconductor nanoparticle. We report on enhancements of phonon modes in nanostructured and quantum dots of TiO2, as well as quantum dots of ZnO and PbS. Because plasmon resonances in semiconductor systems are far in the IR, it is likely that some combination of interband and charge-transfer resonances is responsible for the observed enhancement. (publisher abstract modified)