Material Characterization of Self Assembled Copper-Silicide Nanostructures on Si(001), (110), and (111)
thesisposted on 28.10.2014, 00:00 by Poh Keong Ng
Metal-silicide is a compound formed between metal and silicon (Si), which have a wide variety of properties, e.g. metallic in TiSi2, thermoelectric in ReSi1.75, photonic in Mg2Si, semiconducting in Ca3Si4, and superconductivity in LaSi2. A lot of these properties can be enhanced when fabricated at the nanoscale regime. While there is a lot of research focused on metal silicide nanostructures, copper-silicide (Cu-Si) nanostructures are seldom studied. Only recently, Cu-Si nanostructures were discovered to have optical properties in the mid Infra-Red range and act as catalysts in the CVD growth of Si nanowires. Most of these studies were conducted on free standing Cu-Si nanowires, whereas studies on planar or horizontal Cu-Si nanostructures are rare. Therefore, the focus of this thesis is to characterize the basic properties of planar Cu-Si nanostructures that were fabricated on Si(001), Si(110), and Si(111). In this thesis, material composition was characterized with X-ray energy dispersive spectroscopy (XEDS) whereas the crystallography was characterized with electron diffraction pattern in transmission electron microscopy. The thesis work also extends to in situ electrical resistivity and failure current density measurements of Cu-Si nanowires. Finally, size effects of sub 100 nm Cu-Si nanostructures on electronic properties were studied with a scanning tunneling microscope (STM).