Resonant Raman scattering from CdS nanocrystals enhanced by interstitial Mn

Different Raman scattering effects are observed from CdS and Mn-doped CdS nanocrystals (NCs) with an average size of 5.1 nm synthesized by the reverse-micelle method. The intensity of the longitudinal optical (LO) phonon spectrum acquired from the Mn-doped CdS NCs is more than 20 times larger than that from the undoped CdS NCs. Spectroscopic and theoretical analyses reveal that the enhancement is caused by the interstitial Mn dopants, which decrease the NC surface deformation potential due to the small dielectric constant of the metal resulting in enhanced coupling between the LO phonon and surface plasmon.