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Direct Observation of Threading Dislocations in Gan by High Resolution z-contrast imaging

Published online by Cambridge University Press:  02 July 2020

Y. Xin
Affiliation:
Department of Physics, University of Illinois at Chicago, Chicago., IL60607-7059, USA. Solid State Division, Oak Ridge National Laboratorys, Oak Ridge, TN37831-6031, USA.
N.D. Browning
Affiliation:
Department of Physics, University of Illinois at Chicago, Chicago., IL60607-7059, USA.
S.J. Pennycook
Affiliation:
Solid State Division, Oak Ridge National Laboratorys, Oak Ridge, TN37831-6031, USA.
P.D. Nellist
Affiliation:
Cavendish Laboratory, Cambridge University, Madingley Road, Cambridge, CB3 0HE, UK.
S. Sivananthan
Affiliation:
Department of Physics, University of Illinois at Chicago, Chicago., IL60607-7059, USA.
J-P Faurie
Affiliation:
Department of Physics, University of Illinois at Chicago, Chicago., IL60607-7059, USA. CRHEA-CNRS, rue Bernard Gregory, Oak Ridge, 06560, Valbonne, France.
P. Gibart
Affiliation:
CRHEA-CNRS, rue Bernard Gregory, Oak Ridge, 06560, Valbonne, France.
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Extract

Wide gap nitride semiconductors have attracted significant attention recently due to their promising performance as short-wavelength light emitting diodes (LEDs) and blue lasers. One interesting issue concerning GaN is that the material is relatively insensitive to the presence of a density of dislocations which is six orders of magnitude higher than that for III-V arsenide and phosphide based LEDs. Although it is well known that these dislocations originate at the film-substrate interface during film growth, thread through the whole epilayer with line direction along <0001> and are perfect dislocations with Burgers vectors of a, c, or c+a, the reason why they have such a small effect on the properties of GaN is unclear.

To develop a fundamental understanding of the properties of these dislocations, the core structures are studied here by high resolution Z-contrast imaging in a 300kV VG HB603 scanning transmission electron microscope (STEM) with a resolution of 0.13nm.

Type
Microscopy of Semiconducting and Superconducting Materials
Copyright
Copyright © Microscopy Society of America

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References

References:

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3. Research sponsored by DOE under grant number DOE DE-GF02-96ER45610 and contract DEAC05- 96OR22464 with Lockheed Martin Energy Research Corporation, and by an appointment to the ORNL Postdoctoral Research Program administered jointly by ORNL and ORISEGoogle Scholar