Mobility and Saturation Velocity in Graphene on Silicon Dioxide

Transport properties of exfoliated graphene samples on SiO2 are examined from four-probe electrical measurements combined with electrical and thermal modeling. Data are analyzed with practical models including gated carriers, thermal generation, “puddle” charge, and Joule heating. Graphene mobility is characterized as a function of carrier density at temperatures from 300 to 500 K. In addition, electron drift velocity is obtained at high electric fields up to 2 V/μm, at both 80 K and 300 K. Mobility displays a peak vs. carrier density and decreases with rising temperature above 300 K. The drift velocity approaches saturation at fields >1 V/μm, shows an inverse dependence on carrier density (~n^-1/2), and decreases slightly with temperature. Saturation velocity is >3×10^7 cm/s at low carrier density, and remains greater than in Si up to 1.2×10^13 cm^-2 density. Transport appears primarily limited by the SiO2 substrate, but results suggest intrinsic graphene saturation velocity could be more than twice that observed here.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Electrical & Computer Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2010

Author dc:creator

• Dorgan, Vincent E.

Contributors dc:contributor

• Pop, Eric

• graphene
• mobility
• high-field

Statement dc:rights

• Copyright 2010 Vincent E. Dorgan

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/16801

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/16801