| Autor: |
Bladt E; Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium., van Dijk-Moes RJ; Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands., Peters J; Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands., Montanarella F; Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands., de Mello Donega C; Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands., Vanmaekelbergh D; Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands., Bals S; Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium. |
| Abstrakt: |
Heteronanocrystals consisting of a CdSe core and a giant CdS shell have shown remarkable optical properties which are promising for applications in opto-electrical devices. Since these properties sensitively depend on the size and shape, a morphological characterization is of high interest. Here, we present a high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) study of CdSe (core)/CdS (giant shell) heteronanocrystals. Electron tomography reveals that the nanocrystals have a bullet shape, either ending in a tip or a small dip, and that the CdSe core is positioned closer to the tip (or dip) than to the hexagonal base. Based on a high resolution HAADF-STEM study, we were able to determine all the surface facets. We present a heuristic model for the different growth stages of the CdS crystal around the CdSe core. |
