Step edge influence on barrier height and contact area in vertical heterojunctions between epitaxial graphene and n-type 4H-SiC

Vertical rectifying contacts of epitaxial graphene grown by Si sublimation on the Si-face of 4H-SiC epilayers were investigated. Forward bias preferential conduction through the step edges was correlated by linear current density normalization. This phenomenon was observed on samples with 2.7–5.8 mo...

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Bibliographic Details
Published in:Applied physics letters 2014-02, Vol.104 (7)
Main Authors: Tadjer, M. J., Anderson, T. J., Myers-Ward, R. L., Wheeler, V. D., Nyakiti, L. O., Robinson, Z., Eddy, C. R., Gaskill, D. K., Koehler, A. D., Hobart, K. D., Kub, F. J.
Format: Article
Language:English
Subjects:
Applied physics
APPROXIMATIONS
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
CURRENT DENSITY
Electric contacts
Epitaxial growth
EPITAXY
GRAPHENE
HETEROJUNCTIONS
N-TYPE CONDUCTORS
SILICON
Silicon carbide
SILICON CARBIDES
SUBLIMATION
TEMPERATURE DEPENDENCE
X ray spectra
X-RAY PHOTOELECTRON SPECTROSCOPY
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Summary:Vertical rectifying contacts of epitaxial graphene grown by Si sublimation on the Si-face of 4H-SiC epilayers were investigated. Forward bias preferential conduction through the step edges was correlated by linear current density normalization. This phenomenon was observed on samples with 2.7–5.8 monolayers of epitaxial graphene as determined by X-ray photoelectron spectroscopy. A modified Richardson plot was implemented to extract the barrier height (0.81 eV at 290 K, 0.99 eV at 30 K) and the electrically dominant SiC step length of a Ti/Al contact overlapping a known region of approximately 0.52 μm wide SiC terraces.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4866024