Simultaneous growth of ZnSe cactus-like structures and novel microflowers of selenium

We report here the simultaneous growth of ZnSe cactus-like structures with nanorods emerging from their surface and selenium microflowers using Zn and Se powders as precursors. ZnSe cactuses were obtained by solid state chemical reaction whereas selenium microflowers were obtained by thermal evaporation and condensation process. ZnSe cactuses consist of spheres with diameter range 2-3 mu m having nanorods with diameter in the range 60-90 nm on the exterior surface. The mixture of zinc and selenium powders with few drops of aqueous ammonia loaded in semicircular long alumina boat was heated inside horizontal tube furnace at 500 degrees C for 180 min under ammonia atmosphere. The structural, compositional and morphological characterizations have been performed by means of Scanning Electron Microscope (SEM), the Energy Dispersive Spectroscopy (EDS) and X-ray diffraction (XRD). Room temperature photoluminescence (PL) measurement of as-synthesized products show two intensive peaks centered at 404 nm and 427 nm (2.85 eV), which are attributed to the band edge emission of ZnSe. These two strong emission bands are blue shifted; this blue shift is because of quantum size confinement effect of nanostructures. A very weak peak centered at 464 nm (2.67 eV) is also observed in our sample which is exactly equivalent to the peak associated with the bulk ZnSe, and is attributed to near band edge emission (NBE) for the ZnSe nanostructures. (C) 2011 Elsevier B.V. All rights reserved.