Graphene Growth, Doping, and Characterization for Device Applications

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Material Information

Title:
Graphene Growth, Doping, and Characterization for Device Applications
Physical Description:
1 online resource (105 p.)
Language:
english
Creator:
Berke, Kara
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Physics
Committee Chair:
HEBARD,ARTHUR F
Committee Co-Chair:
RINZLER,ANDREW GABRIEL
Committee Members:
BISWAS,AMLAN
STANTON,CHRISTOPHER JAY
GILA,BRENT P

Subjects

Subjects / Keywords:
graphene
Physics -- Dissertations, Academic -- UF
Genre:
Physics thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
This dissertation aims to describe fundamental physics concepts regarding the fabrication and characterization of graphene for device applications. Ultimately, the goal of this research is to further knowledge of graphene systems in hopes that commercial applications can soon be The first chapter introduces the reader to graphene, beginning with a brief history of its discovery in 2004 and moving on to cover basic structural and electrical properties. A basic knowledge of solid state physics is assumed. The second chapter describes some of the common research techniques employed in subsequent chapters. This includes chemical vapor deposition synthesis methods used to produce the graphene used in Chapters 3 and 4. Also included is a brief explanation of the graphene Raman spectrum. Raman spectroscopy is used extensively throughout this dissertation, and an understanding of the underlying physical principles is key to interpreting the data. In chapter three, we investigate surface charge transfer as a means of doping graphene to increase the density of charge carriers. By applying the organic material bis(trifluoromethanesulfonyl)amide (TFSA) to the graphene surface, the resistivity of the samples decreases by 70%. We observe a dramatic increase in the hole concentration after doping, with only minimal reduction of carrier mobility. Raman spectra are consistent with hole doping, but more importantly indicate that the overall quality of the graphene is preserved during the process. Transmittance measurements are taken in the visible and near-infrared ranges indicating that TFSA-doping does not significantly increase overall sample reflectance. This has allowed TFSA-doped graphene to be implemented into a graphene/n-Si solar cell to achieve a record-breaking 8.6% power conversion efficency, and shows promise for other optoelectronic applications. Chapter four investigates the affect of lattice-matching between graphene and organic semiconductors on a Schottky Junction diode. This time, instead of applying an organic liquid to the graphene surface, the organic small molecule pentacene is deposited directly onto graphene by vapor deposition. Similarity between the structure of pentacene and graphene (both are comprised of hexagonal carbon subunits) allows the first few layers of pentacene molecules to adopt an orientation almost parallel to the graphene surface, whereas they typically adopt a perpendicular orientation when deposited on metallic substrates. A parallel orientation is preferable for vertical device architectures as it aligns the pentacene's high mobility axis in the direction of charge transport. However, diode performance was hindered by a large density of charge trapping sites, leading to a combination of Poole-Frenkel transport and thermionic emission; whereas in an ideal schottky diode, transport would be dominated by thermionic emission. The last chapter focuses on an alternative graphene growth process through epitaxial growth on SiC substrates via pulsed laser annealing (PLA). This process is further refined by using ion implantation as a means to selectively amorphize the sample surface prior to PLA to achieve graphitic growths in predetermined areas on the substrate.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Kara Berke.
Thesis:
Thesis (Ph.D.)--University of Florida, 2013.
Local:
Adviser: HEBARD,ARTHUR F.
Local:
Co-adviser: RINZLER,ANDREW GABRIEL.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2015-12-31

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0046289:00001