title: Enhanced surface-excitonic emission in ZnO/Al(2)O(3) core-shell nanowires.
abstract: We report the influence of an Al(2)O(3) shell on the photoluminescence emission of ZnO nanowires. At room temperature, the spectrum of the core-shell nanowires shows a strong reduction of the relative intensity of the green defect emission with respect to the near-band-edge emission. At 5 K an increase of the relative intensity of the surface exciton band with respect to the donor-bound exciton emission is observed. Annealing the core-shell nanowires at 500 °C does not increase the green defect luminescence at 5 K. We propose a model explaining the spectral changes.
authors.affiliation: Institute of Semiconductor Optics, University of Bremen, Otto-Hahn-Allee 1, D-28359 Bremen, Germany.
authors.forename: J-P
authors.initials: JP
authors.lastname: Richters
authors.forename: T
authors.initials: T
authors.lastname: Voss
authors.forename: D S
authors.initials: DS
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Scholz
authors.forename: M
authors.initials: M
authors.lastname: Zacharias