Keywords
Graphene, molybednum disulfide, stm, atomic hydrogen, graphene based sensors
Abstract
Novel two dimensional nanoscale materials like graphene and metal dichalcogenides (MX2) have attracted the attention of the scientific community, due to their rich physics and wide range of potential applications. It has been shown that novel graphene based transparent conductors and radiofrequency transistors are competitive with the existing technologies. Graphene’s properties are influenced sensitively by adsorbates and substrates. As such not surprisingly, physical properties of graphene are found to have a large variability, which cannot be controlled at the synthesis level, reducing the utility of graphene. As a part of my doctorate dissertation, I have developed atomic hydrogen as a novel technique to count the scatterers responsible for limiting the carrier mobility of graphene field effect transistors on silicon oxide (SiO2) and identified that charged impurities to be the most dominant scatterer. This result enables systematic reduction of the detrimental variability in device performance of graphene. Such sensitivity to substrates also gives an opportunity for engineering device properties of graphene using substrate interaction and atomic scale vacancies. Stacking graphene on hexagonal boron-nitride (h-BN) gives rise to nanoscale periodic potential, which influences its electronic graphene. Using state-of-the-art atomic-resolution scanning probe microscope, I correlated the observed transport properties to the substrate induced extrinsic potentials. Finally in efforts to exploit graphene’s sensitivity to discover new sensor technologies, I have explored noncovalent functionalization of graphene using peptides. Molybdenum disulfide (MoS2) exhibits thickness dependent bandgap. Transistors fabricated from single layer MoS2 have shown a high on/off ratio. It is expected that ad-atom engineering can be used to induce on demand a metal-semiconductor transition in MoS2. In this direction, I have iii explored controlled/reversible fluorination and hydrogenation of monolayer MoS2 to potentially derive a full range of integrated circuit technology. The in-depth characterization of the samples is carried out by Raman/photoluminescence spectroscopy and scanning tunneling microscopy
Notes
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Graduation Date
2014
Semester
Spring
Advisor
Ishigami, Marsahiro
Degree
Doctor of Philosophy (Ph.D.)
College
College of Sciences
Department
Physics
Degree Program
Physics
Format
application/pdf
Identifier
CFE0005190
URL
http://purl.fcla.edu/fcla/etd/CFE0005190
Language
English
Release Date
May 2014
Length of Campus-only Access
None
Access Status
Doctoral Dissertation (Open Access)
Subjects
Dissertations, Academic -- Sciences, Sciences -- Dissertations, Academic
STARS Citation
Katoch, Jyoti, "Electronic Properties And Atomic Scale Microscopy Of Two Dimensional Materials: Graphene And Molybdenum Disulfide" (2014). Electronic Theses and Dissertations. 3030.
https://stars.library.ucf.edu/etd/3030