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Structural Defects in Laterally Overgrown GaN Layers Grown on Non-polar Substrates

Published online by Cambridge University Press:  01 February 2011

Zuzanna Liliental-Weber
Affiliation:
z_liliental-weber@lbl.gov, Lawrence Berkeley National Laboratory, Materials Science Division, 1 Cyclotron Rd, M/S 62R0203-8255, BERKELEY, CA, 94720-8139, United States, 510-486-6276, 510-486-4995
X. Ni
Affiliation:
nix@vcu.edu, Virginia Commonwealth University, Richmond, VA, 23284, United States
H. Morkoc
Affiliation:
hmorkoc@vcu.edu, Virginia Commonwealth University, Richmond, VA, 23284, United States
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Abstract

Transmission electron microscopy was used to study defects in lateral epitaxial layers of GaN which were overgrown on a template of a-plane (1120) GaN grown on (1102) r-plane Al2O3. A high density of basal stacking faults is formed in these layers because the c-planes of wurtzite structure are arranged along the growth direction. Density of these faults is decreasing at least by two orders of magnitude lower in the wings compared to the seed areas. Prismatic stacking faults and threading dislocations are also observed, but their densities drastically decrease in the wings. The wings grow with opposite polarities and the Ga-wing width is at least 6 times larger than N-wing and coalescence is rather difficult. Some tilt and twist was detected using Large Angle Convergent Beam Electron Diffraction.

Type
Research Article
Copyright
Copyright © Materials Research Society 2007

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References

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