Carrier Transport in Graphene, Graphene Nanoribbon and GaN HEMTs

Doctoral Dissertation
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Abstract

Graphene has a linear energy momentum dispersion and its Fermi velocity is vf=10^8 cm/s. This high carrier velocity and its perfect two-dimensional structure make it suitable for high speed electronic devices. In this work, we study the carrier transport in graphene and quasi-one dimensional graphene nanoribbons. The current-carrying capability in graphene under high fields is investigated by numerical simulations. The simulations reveal the roles of the hot-phonon effct and carrier-carrier scatterings in graphene under high fields. The effect of line edge roughness on mobility in sub-10 nm graphene nanoribbons is studied analytically. The results indicate the mobility in sub-10 nm graphene nanoribbons is limited by edge roughness scatterings and agree with experimental work. In addition, we explore inter-band tunneling in graphene and graphene nanoribbons and the current-voltage characteristics of their p-n junctions are calculated. Finally, an optical-phonon limited velocity model is extended from carbon-based materials to III-nitride semiconductors, which have comparable optical phonon scattering rates. The electron-phonon interaction in graphene and III-Nitride semiconductors have similarities characterized by light mass atoms (C or N). Thus, high-field transport in both materials have similarities which enable analytical modeling of radio frequency performance in these materials. GaN-based transistor performance is studied based on the model.

Attributes

Attribute NameValues
URN
  • etd-04162012-232508

Author Tian Fang
Advisor Gregory Snider
Contributor Alan Seabaugh, Committee Member
Contributor Gregory Snider, Committee Member
Contributor Debdeep Jena, Committee Member
Contributor Mark Wistey, Committee Member
Contributor Huili Xing, Committee Member
Degree Level Doctoral Dissertation
Degree Discipline Electrical Engineering
Degree Name PhD
Defense Date
  • 2012-02-23

Submission Date 2012-04-16
Country
  • United States of America

Subject
  • carrier transport

  • graphene

  • GaN

  • graphene nanoribbon

  • high electron mobility transistor

Publisher
  • University of Notre Dame

Language
  • English

Record Visibility and Access Public
Content License
  • All rights reserved

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