Graphite-graphene semiconductor junctions and magneto-dielectric coupling in Schottky diodes
by Tongay, Sefaattin, Ph.D., UNIVERSITY OF FLORIDA, 2010, 189 pages; 3447022

Abstract:

The goal of this dissertation is to incorporate graphite and graphene into today's semiconductor technology as a Schottky barrier diodes (metal/semiconductor junctions) that are widely used in metal semiconductor field effect transistors (MESFETs), high electron mobility transistors (HEMTs), high temperature and frequency devices, solar cells and sensors/detectors. The first part of the dissertation aims to give the reader a general idea about the physics at the metal-semiconductor junctions and essential theory background.

The second chapter of the dissertation questions effects of temperature and magnetic field on the diode characteristics of Schottky junctions. In this chapter, we present observation of negative magnetocapacitance on GaAs:Si/Au junctions and fully equipped with the theory, we present a phenomenological explanation for the observed effect.

In the third chapter, we for the first time introduce multi-layer-graphene as a metal (semimetal) electrode to form Schottky barriers on various technologically significant semiconductors such as Si, GaAs, SiC and GaN. Multi-layer-graphene/ semiconductor junctions not only display good current-voltage (I - V) and capacitance-voltage (C - V) characteristics but also are significant since the Schottky barrier height and characteristics are mainly governed by the interaction and bond formation at few layers on the metal and semiconductor interface. This automatically implies that the presented results also hold for graphene/semiconductor junctions.

Chapter 4, takes the Schottky formation at the multi-layer-graphene(graphene)/ semiconductor junction to another level and aims to change the Fermi level of the metal electrode by intercalation with Bromine and tune the barrier height. Observed results are significant in MESFET technology since different barrier height are desired depending on the application.

The remainder of the dissertation, focuses on the properties of graphite and graphene to have more understanding about the content presented in the previous chapters. Chapter 5, gives a brief theory background about graphite and graphene while Chapter 6 and Chapter 7 discuss electrical properties of graphite at high temperatures where it starts to decouple from each graphene layer and acts as bi-layer graphene and with bromine intercation where there is c-axis lattice constant expansion and each graphene plane becomes more isolated. Chapter 8, gives a detailed description about epitaxial graphene growth in SiC by joule annealing technique, and we end the chapter with future directions.

 
AdviserArthur F. Hebard
SchoolUNIVERSITY OF FLORIDA
SourceDAI/B 72-05, p. , Mar 2011
Source TypeDissertation
SubjectsElectromagnetics; Condensed matter physics; Materials Science
Publication Number3447022
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