Spacer Thickness Dependence of Photoluminescence and Raman Scattering Spectra in Au/Spacer/CdSe-Nanoparticle Multilayers

AbstractWe report photoluminescence (PL) and Raman scattering (RS) spectra in Au/spacer/CdSe-nanoparticle multilayers as a function of the distance between the Au film and the CdSe-nanoparticle monolayer. Both the PL and RS intensities were enhanced when the Au-CdSe distance was large and decreased with a decrease in distance. The influence of the localized surface plasmons on the optical properties of the CdSe nanoparticles is discussed. PACS: 78.67.Bf; 78.30.Fs; 78.55.E

Intersubband electronic Raman scattering in narrow GaAs single quantum wells dominated by single-particle excitations

We measured resonant Raman scattering by intersubband electronic excitations in GaAs/AlAs single quantum wells (QWs) with well widths ranging from 8.5 to 18 nm. In narrow (less than 10 nm) QWs with sufficiently high electron concentrations, only single-particle excitations (SPEs) were observed in intersubband Raman scattering, which was confirmed by the well-width dependence of Raman spectra. We found characteristic variations in Raman shift and line shape for SPEs with incident photon energy in the narrow QWs.Comment: 5 pages including 4 figure

Photoluminescence dynamics of GaN under intense band-to-band and exciton resonant excitation

We have studied the dynamics of highly dense exciton and electron-hole (e-h) systems in GaN by means of optical Kerr-gate time-resolved photoluminescence (PL) spectral measurements. In high-density e-h pairs above the Mott density, the broad electron-hole plasma emission appears at first, and then the narrow PL due to the biexciton and the inelastic exciton-exciton scattering is observed. When the pump light resonantly excites the A excitons, highly dense e-h systems with low effective temperatures are formed, and unique PL bands are observed. These PL peaks can be explained by a picture that the A excitons are scattered into the A, B , and C bands

Energy transfer in mixed CdSe and Au nanoparticle monolayers studied by simultaneous photoluminescence and Raman spectral measurements

We report photoluminescence (PL) and Raman-scattering (RS) spectra in close-packed CdSe/Au mixed nanoparticle (NP) monolayers as a function of the ratio of CdSe to Au NPs in the film. The RS intensity showed slight enhancement with an increase in the Au NPs, while the PL intensity decreased dramatically. These results were explained by an energy-transfer (ET) model considering weak electromagnetic-enhancement factors estimated from the RS studies and ET rates from CdSe to Au NPs obtained from the time-resolved PL spectra