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Atomic structure of pyramidal defects in GaN:Mg: Influence of annealing
Author(s) -
LilientalWeber Z.,
Tomaszewicz T.,
Zakharov D.,
O'Keefe M.,
Hautakangas S.,
Saarinen K.,
Freitas J. A.,
Henry R. L.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200565458
Subject(s) - metalorganic vapour phase epitaxy , annealing (glass) , photoluminescence , materials science , transmission electron microscopy , vacancy defect , doping , annihilation , hexagonal crystal system , crystallography , molecular physics , analytical chemistry (journal) , chemistry , optoelectronics , nanotechnology , epitaxy , metallurgy , physics , layer (electronics) , quantum mechanics , chromatography
The atomic structure of the characteristic defects (Mg‐rich hexagonal pyramids) in p‐doped bulk and MOCVD GaN:Mg thin films grown with Ga polarity was determined at atomic resolution by direct reconstruction of the scattered electron wave in a transmission electron microscope. Small cavities were present inside the defects, confirmed also with positron annihilation. The inside walls of the cavities were covered by GaN of reverse polarity compared to the matrix. Annealing of the MOCVD layers lead to slight increase of the defect size and an increase of the room temperature photoluminescence intensity. Positron annihilation confirms presence of vacancy clusters of different sizes triggered by the Mg doping in as‐grown samples and decrease of their concentration upon annealing at 900 and 1000 °C. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)