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Structural properties of semipolar Al x Ga 1− x N( $1\bar {1}03$ ) films grown on ZnO substrates using room temperature epitaxial buffer layers
Author(s) -
Ueno Kohei,
Kobayashi Atsushi,
Ohta Jitsuo,
Fujioka Hiroshi
Publication year - 2010
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.201026209
Subject(s) - materials science , epitaxy , bar (unit) , reciprocal lattice , crystallography , pulsed laser deposition , crystallinity , mole fraction , substrate (aquarium) , dislocation , analytical chemistry (journal) , thin film , diffraction , nanotechnology , optics , chemistry , composite material , physics , oceanography , layer (electronics) , chromatography , geology , meteorology
$1\bar {1}03$ We have grown Al x Ga 1− x N films on semipolar ZnO ( $1\bar {1}03$ ) substrates by pulsed laser deposition (PLD). The direct growth of Al 0.25 Ga 0.75 N on ZnO ( $1\bar {1}03$ ) substrates at 850 °C results in the formation of c ‐axis oriented materials with poor crystallinity due to serious interfacial reactions that occur between Al 0.25 Ga 0.75 N and ZnO. However, epitaxial Al x Ga 1− x N ( $1\bar {1}03$ ) films can be grown on ZnO substrates by the incorporation of PLD room temperature (RT) epitaxial buffer layers. From X‐ray symmetric reciprocal space mapping studies, the [ $1\bar {1}03$ ] directions of all Al x Ga 1− x N ( $1\bar {1}03$ ) layers are slightly tilted toward the c ‐axis from that of the ZnO substrate. We also found that the magnitude of the crystallographic tilt of Al x Ga 1− x N ( $1\bar {1}03$ ) increases with AlN mole fraction x . This tendency can be explained by a reduction in the average misfit dislocation interval due to the increasing lattice mismatch between Al x Ga 1− x N and ZnO with AlN mole fraction x .