Published online by Cambridge University Press: 20 August 2012
ZnO films with a nanostructure dominated by 150-200 nm size highly c-axis oriented nanorod arrays were deposited by hydrothermal synthesis over surface activated quartz substrates. Sulfur infiltration and growth of ZnO1-xSx over ZnO nanorods was carried out by chemiplating process using slow hydrolysis of thiourea solution at 95°C. Formation of ZnO1-xSx nanocrystals of 20-30 nm size over (0001) facets of the ZnO rods is shown. With progressive growth of ZnO1-xSx nanocrystal and full ZnO nanorod coverage, the formation ZnO/ZnO1-xSx core –shell nanostructure is realized. X-ray photoelectron spectroscopy analysis shows chemical shifts in O1s and S2p spectra confirming the formation of ZnO1-xSx (0.1≤x≤0.2) nanocrystal shell. Reduction in optical band gap from a 3.24 eV for ZnO nanorod core to 2.78 eV for the ZnO1-xSx shell is consistent with the band gap bowing effect due to sulfur addition over the ZnO nanorod surface.