title: Atomic Structure of Wurtzite CdSe (Core)/CdS (Giant Shell) Nanobullets Related to Epitaxy and Growth.
abstract: 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.
authors.affiliation: Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Eva
authors.initials: E
authors.lastname: Bladt
authors.affiliation: Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands.
authors.forename: Relinde J A
authors.initials: RJ
authors.lastname: van Dijk-Moes
authors.affiliation: Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands.
authors.forename: Joep
authors.initials: J
authors.lastname: Peters
authors.affiliation: Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands.
authors.forename: Federico
authors.initials: F
authors.lastname: Montanarella
authors.affiliation: Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands.
authors.forename: Celso
authors.initials: C
authors.lastname: de Mello Donega
authors.affiliation: Debye Institute for Nanomaterials Science, University of Utrecht , 3512 JE Utrecht, Netherlands.
authors.forename: Daniël
authors.initials: D
authors.lastname: Vanmaekelbergh
authors.affiliation: Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Sara
authors.initials: S
authors.lastname: Bals