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Structural And Electronic Properties of GaN/AL Interfaces

Published online by Cambridge University Press:  10 February 2011

S. Picozzi
Affiliation:
INFM - Dip. Fisica - Univ. L'Aquila, 67010 Coppito (L'Aquila), Italy
A. Continenza
Affiliation:
INFM - Dip. Fisica - Univ. L'Aquila, 67010 Coppito (L'Aquila), Italy
S. Massidda
Affiliation:
INFM - Dip. Scienze Fisiche - Univ. Cagliari, 09124 Cagliari, Italy
A. J. Freeman
Affiliation:
Dept. of Physics and Astronomy and Materials Research Center - Northwestern Univ., Evanston, IL 60208 (U.S.A.)
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Abstract

The structural and electronic properties of the GaN/Al interface are determined from first principles local density full potential linearized augmented plane wave (FLAPW) calculations. The charge distribution of the gap states as a function of the distance from the interface shows that the gap states induced into the semiconductor by the presence of Al are strongly localized in the junction region. Furthermore, we find that Al does not provide good ohmic contacts on the clean nitrides considered, in contrast with experimental results on chemically treated GaN, but in agreement with recent measurements on the clean surface[1]. We also study some auxiliary systems (all grown on a GaN substrate), i.e. the Al/AlN interface, the GaN/AlN heterojunction and the GaN/Al with an AlN intralayer (GaN-AlN/Al). The transitivity rule for the GaN/Al, AlN/Al and GaN/AlN interfaces is fairly well satisfied and small differences must be ascribed to differences in the interface morphology. Finally, we find that the AIN intralayer does not significantly affect the p-type Schottky barrier height of the GaN/Al interface.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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