- Collection:
- Atlanta University and Clark Atlanta University Theses and Dissertations
- Title:
- Structural and electronic properties of boron monolayer sheets and nitrogen-seeded epitaxial graphene, 2014
- Creator:
- Mudiyanselage, Asanga B. Arampath
- Date of Original:
- 2010/2019
- Subject:
- Degrees, Academic
Dissertations, Academic - Location:
- United States, Georgia, Fulton County, Atlanta, 33.749, -84.38798
- Medium:
- theses
dissertations - Type:
- Text
- Format:
- application/pdf
- Description:
- We employ a global optimization method to predict two-dimensional (2D) nanostructures through the particle swarm optimization (PSO) algorithm. By performing PSO simulations, we predict new stable structures of boron monolayer sheets for a wide range of boron concentrations. We present a new class of boron sheets, composed of triangular and hexagonal motifs, which are more likely to be the precursors of boron nanotubes. We describe a simple and clear picture of electronic bonding in boron sheets and highlight the importance of three-center bonding and its competition with two-center bonding, which can also explain the stability of recently discovered boron monolayer sheets. The graphene-based electronics is an intriguing prospective for replacing silicon for next-generation of transistors. Practical application of graphene based materials requests a band gap. We present results from first-principles density-function calculation for semiconducting graphene based on nitrogen-seeded epitaxial graphene. A small fraction of covalently-bonded nitrogen leads to a band gap opening in epitaxial graphene and a transition from a semi metallic to a semiconducting state. The induced gap is shown to be attributed to the modification of the 1t conjugation of epitaxial graphene. The resulting nitrogen-seeded graphene opens a band gap about 0.8 eV, in good agreement with experimental observations.
Date of award: 7/1/2014
Degree type: thesis
Degree name: Master of Science (MS)
Granting institution: Clark Atlanta University
Department: Physics
Advisor: Wang, Xiao-Oian
Advisor: Msezane, Alfred Z.
Advisor: Chen, Zhifan - Metadata URL:
- http://hdl.handle.net/20.500.12322/cau.td:2014_mudiyanselage_asanga_b_a
- Holding Institution:
- Atlanta University Center Robert W. Woodruff Library
- Rights: