Raman Scattering for Probing Semiconductor Nanostructures: from Nanocrystal Arrays towards a Single Nanocrystal

Abstract

We present a study of resonant and surface enhanced Raman scattering (SERS) by arrays of CdS, CuS, ZnO, and PbSe nanocrystals (NCs) with various areal density. Resonant Raman scattering by optical phonons and their overtones up to 9th order was observed for ZnO NC arrays by adjusting the laser energy to that of the interband transitions. The resonance enhancement allowed a Raman response from arrays of NCs with a low areal density (down to 10 PbSe NCs per 1 mu m(2)) to be measured. An enhancement of Raman scattering by LO modes in CdS NC arrays by a factor of about 730 due to the resonant SERS effect was demonstrated. SERS effect by optical phonons in CuS NCs with ultra-low areal density formed on laterally ordered arrays of Au nanoclusters was observed.