Thesis (M.S. in mechanical engineering)--Washington State University, December 2006. / Includes bibliographical references (p. 52-53).

Thesis (Ph.D.)(Chemistry)--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (Ph.D)--Physics, Georgia Institute of Technology, 2009. / Committee Co-Chair: Conrad, Edward; Committee Co-Chair: First, Phillip; Committee Member: Carter, Brent; Committee Member: de Heer, Walter; Committee Member: Zangwill, Andrew. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Graphene, a honeycomb lattice of sp2-bonded carbon atoms, has received considerable attention in the scientific community due to its unique electronic properties. Distinct symmetries of the graphene wave functions lead to unusual quantum properties, such as a unique half-integer quantum Hall effect. As an added consequence of these symmetries, back-scattering in graphene is strongly prohibited leading to long coherence lengths of carriers. These charge carriers at low energy exhibit linear energy-momentum dispersion, much like neutrinos. Thus, carriers in graphene can be described as massless Dirac fermions. Graphene grown epitaxially on semiconducting substrates offers the possibility of large-scale production and deterministic patterning of graphene for nanoelectronics. In this work, epitaxial graphene is created on SiC(0001) by annealing in vacuum. Sequential scanning tunneling microscopy (STM) and spectroscopy (STS) are performed in ultrahigh vacuum at a temperature of 4.2 K and 300 K. These atomic-scale studies address the growth, interfacial properties, stacking order, and quasiparticle coherence in epitaxial graphene. STM topographic images show the atomic structure of successive graphene layers on the SiC substrate, as well as the character of defects and adatoms within and below the graphene plane. STS differential conductance (dI/dV) maps provide spatially and energy resolved snapshots of the local density of states. Such maps clearly show that scattering from atomic defects in graphene gives rise to energy-dependent standing wave patterns. We derive the carrier energy dispersion of epitaxial graphene from these data sets by quantifying the dominant wave vectors of the standing waves for each tunneling bias.

Graphene, a single sheet of carbon atoms sp2-bonded in a honeycomb lattice, is a possible all-carbon successor to silicon electronics. Ballistic conduction at room temperature and a linear dispersion relation that causes carriers to behave as massless Dirac fermions are features that make graphene promising for high-speed, low-power devices. The critical advantage of epitaxial graphene (EG) grown on SiC is its compatibility with standard lithographic procedures. Surface X-ray diffraction (SXRD) and scanning tunneling microscopy (STM) results are presented on the domain structure, interface composition and stacking character of graphene grown on both polar faces of semi-insulating 4H-SiC. The data reveal intriguing differences between graphene grown on these two faces. Substrate roughening is more pronounced and graphene domain sizes are significantly smaller on the SiC (0001) Si-face. Specular X-ray reflectivity measurements show that both faces have a carbon rich, extended interface that is tightly bound to the first graphene layer, leading to a buffering effect that shields the first graphene layer from the bulk SiC, as predicted by ab initio calculations. In-plane X-ray crystal truncation rod analysis indicates that rotated graphene layers are interleaved in C-face graphene films and corresponding superstructures are observed in STM topographs. These rotational stacking faults in multilayer C-face graphene preserve the linear dispersion found in single layer graphene, making EG electronics possible even for a multilayer material.