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Compositionally Dependent Band Offsets In Aln/AlxGa1-xN Heterojunctions Measured By Using X-Ray Photoelectron Spectroscopy

Published online by Cambridge University Press:  10 February 2011

R.A. Beach ,
E.C. Piquette ,
R.W. Grant  and
T.C. McGill
R.A. Beach
Affiliation:
T.J. Watson Sr. Laboratories of Applied Physics California Institute of Technology, Pasadena CA 91125
E.C. Piquette
Affiliation:
T.J. Watson Sr. Laboratories of Applied Physics California Institute of Technology, Pasadena CA 91125
R.W. Grant
Affiliation:
T.J. Watson Sr. Laboratories of Applied Physics California Institute of Technology, Pasadena CA 91125
T.C. McGill
Affiliation:
T.J. Watson Sr. Laboratories of Applied Physics California Institute of Technology, Pasadena CA 91125
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Abstract

Although GaN has been extensively studied for applications in both light emitting and high power devices, the AlN/GaN valence band offset remains an area of contention. Values quoted in the literature range from 0.8eV (Martin)[1] to 1.36eV (Waldrop)[2]. This paper details an investigation of the AIN/AlxGa1-xN band offset as a function of alloy composition. We find an AlN/AlxGa1-xN valence band offset that is nearly linear with Al content and an end point offset for AlN/GaN of 1.36 ± 0.1 eV. Samples were grown using radio frequency plasma assisted molecular beam epitaxy and characterized with x-ray photoelectron spectroscopy(XPS). Core-level and valence-band XPS data for AIN (0001) and AlxGa1-xN (0001) samples were analyzed to determine core-level to valence band maximum (VBM) energy differences. In addition, oxygen contamination effects were tracked in an effort to improve accuracy. Energy separations of core levels were obtained from AlN/AlxGa1-xN(0001) heterojunctions. From this and the core-level to valence band maximum separations of the bulk materials, valence band offsets were calculated.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 482 , 1997 , 775
Copyright
Copyright © Materials Research Society 1998

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Footnotes

1

Electronic mail: [email protected]

References

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