title: Biexciton emission and crystalline quality of ZnO nano-objects.
abstract: The design of cost-effective standards for the quality of nano-objects is currently a key issue toward their massive use for optoelectronic applications. The observation by photoluminescence of narrow excitonic and biexcitonic emission lines in semiconductor nanowires is usually accepted as evidence for high structural quality. Here, we perform time-resolved cathodoluminescence experiments on isolated ZnO nanobelts grown by chemical vapor deposition. We observe narrow emission lines at low temperature, together with a clear biexciton line. Still, drastic alterations in both the CL intensity and lifetime are observed locally along the nano-object. We attribute these to non-radiative recombinations at edge dislocations, closing basal plane stacking faults, inhomogeneously distributed along the NB length. This leads us to the conclusion that the observation of narrow excitonic and biexcitonic emission lines is far from sufficient to grade the quality of a nano-object.
authors.affiliation: Institute of Condensed Matter Physics, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland. pierre.corfdir@epfl.ch
authors.forename: Pierre
authors.initials: P
authors.lastname: Corfdir
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abid
authors.forename: Anas
authors.initials: A
authors.lastname: Mouti
authors.forename: Pierre A
authors.initials: PA
authors.lastname: Stadelmann
authors.forename: Elisa
authors.initials: E
authors.lastname: Papa
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Ansermet
authors.forename: Jean-Daniel
authors.initials: JD
authors.lastname: Ganière
authors.forename: Benoît
authors.initials: B
authors.lastname: Deveaud-Plédran