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Characterisation of Epitaxial Laterally Overgrown Gallium Nitride Using Transmission Electron Microscopy
Author(s) -
Tricker D.M.,
Jacobs K.,
Humphreys C.J.
Publication year - 1999
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199911)216:1<633::aid-pssb633>3.0.co;2-o
Subject(s) - coalescence (physics) , materials science , epitaxy , transmission electron microscopy , dislocation , gallium nitride , sapphire , optoelectronics , optics , condensed matter physics , crystallography , composite material , layer (electronics) , chemistry , nanotechnology , laser , physics , astrobiology
We describe structural characterisation of epitaxial laterally overgrown (ELOG) GaN by transmission electron microscopy. A reduced dislocation density is observed in laterally overgrown GaN, although dislocations are observed at the centre of the overgrown region, associated with the coalescence of GaN growth fronts. Dislocations which propagate into the overgrown GaN bend over into the basal plane. Where surface pits are present, they are usually hexagonal in shape, bounded by {101‐1} planes, and lie above the silica stripes along the line of coalescence. Threading dislocations are commonly found to emerge at the base of these pits. The light output of LEDs made from ELOG GaN is 40 times greater than that from comparable conventionally grown, high dislocation density GaN.