Structural properties of semipolar AlxGa1−xN($1\bar {1}03$) films grown on ZnO substrates using room temperature epitaxial buffer layers

✍ Scribed by Ueno, Kohei ;Kobayashi, Atsushi ;Ohta, Jitsuo ;Fujioka, Hiroshi

• Book ID: 105366193
• Publisher: John Wiley and Sons
• Year: 2010
• Tongue: English
• Weight: 251 KB
• Volume: 207
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.201026209

✦ Synopsis

Abstract

$1\bar {1}03$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.