title: Optical emission of biaxial ZnO-ZnS nanoribbon heterostructures.
abstract: The electronic structure and optical properties of biaxial ZnO-ZnS heterostructure nanoribbons (NRs) have been investigated using x-ray absorption near-edge structures (XANES) and x-ray excited optical luminescence (XEOL). The XANES were recorded in total electron yield and wavelength-selected photoluminescence yield across the K- and L(3,2)-edges of zinc and sulfur and the K-edge of oxygen. The XEOL from the NRs exhibit a very weak band-gap emission at 392 nm and two intense defect emissions at 491 and 531 nm. The synchrotron x-ray pulse ( approximately 100 ps, 153 ns repetition rate) was used to track the optical decay dynamics from ZnO-ZnS NR, which can be described by two lifetimes (7.6 and 55 ns). Comparison with similar measurements for ZnO and ZnS nanowires reveals that the luminescence from ZnO-ZnS NRs was dominated by the ZnO component of the NR as the ZnS component contributes little. The implication of this observation is discussed.
authors.affiliation: Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7, Canada.
authors.forename: M W
authors.initials: MW
authors.lastname: Murphy
authors.forename: X T
authors.initials: XT
authors.lastname: Zhou
authors.forename: J Y P
authors.initials: JY
authors.lastname: Ko
authors.forename: J G
authors.initials: JG
authors.lastname: Zhou
authors.forename: F
authors.initials: F
authors.lastname: Heigl
authors.forename: T K
authors.initials: TK
authors.lastname: Sham