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Electroreflectance and Photoreflectance Studies of Electric Fields in Pt/GaN Schottky Diodes and AlGaN/GaN Heterostructures

Published online by Cambridge University Press:  11 February 2011

S. Shokhovets
Affiliation:
Institute of Physics
R. Goldhahn
Affiliation:
Institute of Physics
G. Gobsch
Affiliation:
Institute of Physics
O. Ambacher
Affiliation:
Center for Micro- and Nanotechnologies, Technical University Ilmenau, 98684 Ilmenau, Germany
I. P. Smorchkova
Affiliation:
Electrical and Computer Engineering Department and Materials Department, University of California, Santa Barbara, CA 93106, U.S.A.
J. S. Speck
Affiliation:
Electrical and Computer Engineering Department and Materials Department, University of California, Santa Barbara, CA 93106, U.S.A.
U. Mishra
Affiliation:
Electrical and Computer Engineering Department and Materials Department, University of California, Santa Barbara, CA 93106, U.S.A.
A. Link
Affiliation:
Walter Schottky Institute, Technical University Munich, 85748 Garching, Germany
M. Hermann
Affiliation:
Walter Schottky Institute, Technical University Munich, 85748 Garching, Germany
M. Eickhoff
Affiliation:
Walter Schottky Institute, Technical University Munich, 85748 Garching, Germany
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Abstract

We have performed electroreflectance and photoreflectance studies of Pt/GaN Schottky diodes with Ga- and N-face polarity as well as AlGaN/GaN based transistor heterostructures. The experimental data were analyzed using electric field-dependent dielectric functions of GaN and AlGaN. Inhomogeneities in the electric fields were taken into account by application of a multi-layer formalism. We observed an increase of the electric field strength underneath the Schottky contact and in the AlGaN barrier with increasing temperature. The results are explained in terms of temperature dependent densities of ionized impurities and surface charges.

Type
Research Article
Copyright
Copyright © Materials Research Society 2003

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References

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