title: Photoluminescence and photoconductivity of ZnS-coated ZnO nanowires.
abstract: ZnO nanowires (NWs) with a ZnS coating are synthesized in order to modify the surface without changing the diameter of the NWs. They have the wurtzite ZnO at the core and a cubic ZnS at the outer layer. The NWs show a sharp ultraviolet and a broad visible emission of the photoluminescence spectra. Surface modification has led to a change in the position of the maxima of the visible emission in ZnO-ZnS NWs. The photocarrier relaxation under steady UV illumination occurs in ZnO NW arrays but is absent in ZnO-ZnS NW arrays. The dark current value for both type of NWs are similar, whereas the photocurrent value is much higher in the surface-modified NWs. Higher photocurrent value indicates a transport of the photogenerated carriers from the ZnS layer to ZnO during UV illumination. The carrier transport mechanism is proposed through a model.
authors.affiliation: Department of Solid State Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India.
authors.forename: Ashok
authors.initials: A
authors.lastname: Bera
authors.forename: Durga
authors.initials: D
authors.lastname: Basak
mesh_terms: D004553:Electric Conductivity; D004559:Electric Wiring; D008027:Light; D008163:Luminescent Measurements / Q000379:methods*; D008422:Materials Testing; D036103:Nanotechnology / Q000379:methods; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects* / Q000648:ultrastructure; D010777:Photochemistry / Q000379:methods*; D018036:Selenium Compounds / Q000737:chemistry*; D017967:Zinc Compounds / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D018036:Selenium Compounds; D017967:Zinc Compounds; C044696:zinc selenide; D015034:Zinc Oxide