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Physical Sciences and Mathematics Commons

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Dissertations, Theses, and Masters Projects

2008

Condensed Matter Physics

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Full-Text Articles in Physical Sciences and Mathematics

Synthesis And Field Emission Properties Of Carbon Nanostructures, Kun Hou Jan 2008

Synthesis And Field Emission Properties Of Carbon Nanostructures, Kun Hou

Dissertations, Theses, and Masters Projects

This dissertation focuses on developing carbon nanostructures for application as the electron emissive material in novel back-gated triode field emission devices. The synthesis, characterization, and field emission properties of carbon nanostructures, including 1-D carbon nanofibers (CNF), 2-D carbon nanosheets (CNS), and chromium oxide coated carbon nanosheets (CrOx-CNS), are presented in this work.;First, we have fabricated aligned carbon nanofiber based back-gated triode field emission devices and confirmed the operation of these devices. 1-D carbon nanofibers were directly synthesized on blank TiW substrates using direct current plasma enhanced chemical vapor deposition. It was found that the morphology of carbon nanofibers could be …


Correction Of Finite Size Errors In Many-Body Electronic Structure Calculations, Hendra Kwee Jan 2008

Correction Of Finite Size Errors In Many-Body Electronic Structure Calculations, Hendra Kwee

Dissertations, Theses, and Masters Projects

Electronic structure calculations using simulation cells for extended systems typically incorporate periodic boundary conditions as an attempt to mimic the real system with a practically infinite number of particles. Periodic boundary conditions introduce unphysical constraints that give rise to finite-size errors. In mean-field type calculations, the infinite size limit is achieved by simple quadrature in the Brillouin zone using a finite number of k-points. Many-body electronic structure calculations with explicit two-particle interactions cannot avail themselves of this simplification. Direct extrapolation is computationally costly while size correction with less accurate methods is frequently not sufficiently accurate. The Hartree-Fock method neglects the …