Optical Properties Of Epitaxially Grown Submonolayer Cdse/Znse Nanostructures

The optical properties of epitaxially grown CdSe/ZnSe nanostructures with nominal CdSe coverage between 0.15 monolayer (ML) and 0.58 ML are investigated by photoluminescence (PL) and PL excitation spectroscopy at low and high excitation density, time-resolved PL, temperature dependent linewidth analysis, and two-photon excitation spectroscopy. We discuss exciton-phonon complexes in a potential and analyze their dominant dimensionality. The exciton-polaron picture, which is mostly applied to the extreme case of very strong exciton-phonon coupling, is introduced here as a well-suited description of the optical properties of ultra-small semiconductor nanostructures with relaxed quantum confinement.