Sökning: "epitaxial graphene"

Visar resultat 1 - 5 av 25 avhandlingar innehållade orden epitaxial graphene.

  1. 1. Epitaxial Graphene Technology for Quantum Metrology

    Författare :Thomas Yager; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; charge neutrality; optical microscopy; Epitaxial graphene; resistance metrology; silicon carbide; quantum Hall effect; electron transport; bilayer graphene;

    Sammanfattning : Graphene grown on silicon carbide by high-temperature annealing (SiC/G) is a strong contender in the race towards large-scale graphene electronics applications. The unique electronic properties of this system lead to a remarkably robust and accurate Hall resistance quantisation of 0. LÄS MER

  3. 2. Engineering Epitaxial Graphene for Quantum Metrology

    Författare :Hans He; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Epitaxial Graphene; Magnetotransport; Quantum Resistance Metrology; Chemical Doping;

    Sammanfattning : Quantum resistance metrology deals both with the precise and accurate measurement of electrical resistance, by utilizing the quantum hall effect (QHE) in two-dimensional electron gases (2DEGs) such as those based on gallium arsenide (GaAs). Due to the unique properties of graphene, and specifically epitaxial graphene grown on silicon carbide (SiC/G), quantum Hall resistance (QHR) standards based on graphene perform better in a wider parameter space (temperature, current and magnetic field) than conventional semiconducting materials. LÄS MER

  4. 3. Magnetotransport characterization of epitaxial graphene on SiC

    Författare :Samuel Lara Avila; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; quantum metrology; weak localization; magnetotransport; quantum Hall effect; many-electron systems; epitaxial graphene;

    Sammanfattning : Low-temperature magnetotransport is used to characterize graphene grown epitaxially on the silicon face of 4H silicon carbide (SiC/G). Observation of half-integer quantum Hall effect (QHE) in large Hall bars, patterned across several terraces of the SiC substrate, suggest that monolayer graphene grows continuously over defects. LÄS MER

  5. 4. Controlling Electronic and Geometrical Structure of Honeycomb-Lattice Materials Supported on Metal Substrates : Graphene and Hexagonal Boron Nitride

    Författare :Nikolay Vinogradov; Nils Mårtensson; Karsten Horn; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; graphene; h-BN; electronic structure; adsorption; doping; nano-templates; PES; NEXAFS; LEEM; STM; Physics with spec. in Atomic; Molecular and Condensed Matter Physics; Fysik med inriktning mot atom- molekyl- och kondenserande materiens fysik;

    Sammanfattning : The present thesis is focused on various methods of controlling electronic and geometrical structure of two-dimensional overlayers adsorbed on metal surfaces exemplified by graphene and hexagonal boron nitride (h-BN) grown on transition metal (TM) substrates. Combining synchrotron-radiation-based spectroscopic and various microscopic techniques with in situ sample preparation, we are able to trace the evolution of overlayer electronic and geometrical properties in overlayer/substrate systems, as well as changes of interfacial interaction in the latter. LÄS MER

  7. 5. Molecular Doping of Epigraphene for Device Applications

    Författare :Hans He; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Molecular Doping; Graphene; epitaxial graphene; THz; Metrology; Hall Effect;

    Sammanfattning : Epitaxial graphene grown on silicon carbide, or epigraphene, offers in principle a suitable platform for electronic applications of graphene which require scalable, reproducible, and high-quality material. However, one of the main drawbacks of epigraphene lies in the difficulty in controlling its carrier density, which hinders its usefulness in future applications. LÄS MER