Browsing by Author "Arendse, C.J."

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    Evolution of the chemical composition of Sn thin films heated during x-ray photoelectron spectroscopy
    (2019) Modiba, F.; Arendse, C.J.; Oliphant, C.J.; Jordaan, W. A.; Mostert, L
    High-vacuum XPS have been used to analyse the surface modification of a 3 nm-thick Sn thin film on Si (100) before and after annealing up to 450 °C. Increasing the XPS stage temperature led to a reduction in the amount of surface Sn and increasing amounts of O and Si. High-resolution XPS scans revealed the presence of mostly pure Sn and SnO2 for the as-deposited Sn thin film. Increasing the XPS stage temperature to > 232 °C led to the conversion of SnO2 to SnO and an enhancing pure Sn signal. The Si2p and SiO2 peaks become prominent at temperatures > 350 °C, which in combination with scanning electron microscope images, signals the dewetting of the Sn film and subsequent exposure of the underlying Si (100) substrate. XPS depth profiles revealed the presence of a pure Sn metallic core encapsulated by a Sn-oxide shell. Electron microscope images shows a densely packed particulate surface features for the as-deposited Sn thin film. However, these particulate regions increase in size and are more isolated at XPS stage temperatures > 350 °C.
  • Thumbnail Image
    Item
    Filament carburization during the hot-wire chemical vapour deposition of carbon nanotubes
    (University of the Western Cape, 2008) Oliphant, Clive Justin; Arendse, C.J.; Knoesen, Dirk; Dept. of Physics; Faculty of Science
    This study reports on the changes in the structural properties of a tungsten-filament when exposed to a methane / hydrogen ambient for different durations at various filament-temperatures.
  • Thumbnail Image
    Item
    Metal oxide nanocrystalline thin films as buffer layers in organic/ hybrid solar cells
    (University of Western Cape, 2019) Bowers, Norman Mark; Muller, T.F.G.; Arendse, C.J.
    Without reverting to encapsulation, organic bulk - heterojunction solar cells can be protected from the oxidation of the highly reactive low work function cathode metal electrode, by the deposition of metal oxide buffer layers onto an indium-tin oxide (ITO) substrate. The zinc-oxide (ZnO) or titanium dioxide (TiO2) layer can serve as an electron collecting contact. In such a case the ordering of layer deposition is inverted from the traditional layer sequencing, using an additional effect of the metal oxide layer acting as a hole blocking contact