One-step synthesis of low-dimensional CdSe nanostructures and optical waveguide of CdSe nanowires

Low-dimension (1D) semiconductor CdSe nanostructures, including nanosheets, nanoribbons, nanowires and branchlike, have been successfully synthesized in bulk quantities by a simple and low-cost process based on thermal evaporation of CdSe powders onto a silicon substrate. The temperature of the substrates and the concentration of CdSe vapour are the critical parameters for the formation of different morphologies of CdSe nanostructure by scanning electron microscopy and transmission electron microscopy characterization. The growth of nanowires is controlled by the conventional vapour–liquid–solid (VLS) mechanism, while the nanobelts comply with a combination of VLS and vapour–solid (VS) processes; the formation of sheets primarily follows the nanobelt formation with more VS growth. The photoluminescence properties of CdSe nanowires were studied by confocal microscopy; a clear optical waveguide was observed and discussed for the first time.