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Transmission Electron Holography of a GaN/AlxGal-xN Heterostructure

Published online by Cambridge University Press:  02 July 2020

Y.C. Wang ,
C. Kisielowski ,
E. C. Nelson  and
M.A. O’Keefe
Y.C. Wang
Affiliation:
N, ational Center for Electron Microscopy, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, 94720
C. Kisielowski
Affiliation:
N, ational Center for Electron Microscopy, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, 94720
E. C. Nelson
Affiliation:
N, ational Center for Electron Microscopy, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, 94720
M.A. O’Keefe
Affiliation:
N, ational Center for Electron Microscopy, Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA, 94720
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Extract

GaN and the related AlN semiconducting materials have recently attracted considerable attention because of their versatile applications for optoelectronics. Large stresses are present in the GaN/AlN thin-film heterostructure and can exceed GPa's. They originate from a large lattice mismatch between the substrate(sapphire)/GaN (14%) and the AlN/GaN interface (-2.7%) in quantum well structures. The strain is expected to induce local piezoelectric fields in these polar materials. It is essential for a further development of GaN based thin films to fully understand the formation and the local strength of these fields. Previous studies show that there are unusual large fluctuations of the patterns in lattice images present across GaN/AlxGa1-xN and GaN/InyGa1-yN quantum wells. They are attributed to compositional fluctuations and have been studied by quantitative high resolution electron microscopy. Differences between the strain profiles and the electrostatic (scattering) potential profiles were observed.

Type
Compositional Mapping With High Spatial Resolution
Information
Microscopy and Microanalysis , Volume 4 , Issue S2: Proceedings: Microscopy & Microanalysis '98, Microscopy Society of America 56th Annual Meeting, Microbeam Analysis Society 32nd Annual Meeting, Atlanta, Georgia July 12-16, 1998 , July 1998 , pp. 132 - 133
Copyright
Copyright © Microscopy Society of America

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References

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6. This work is supported by the Director Office of Energy Research, Office of Basic Energy Science, Materials Science Division, of the US Department of Energy under Contract No. DE-AC03-76SF00098 and by Philips Electron Optics.Google Scholar