Improvements in (112̅2) semipolar GaN crystal quality by graded superlattices

• Published in: Thin solid films Vol. 520; no. 6; pp. 1909 - 1912
• Main Authors: Xu, S.R., Zhang, J.C., Cao, Y.R., Zhou, X.W., Xue, J.S., Lin, Z.Y., Ma, J.C., Bao, F., Hao, Y.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 2012; Elsevier
• Subjects: Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Defects and impurities in crystals; microstructure; Exact sciences and technology; GaN; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Other semiconductors; Physics; Semipolar; Specific materials; Stacking faults and other planar or extended defects; Structure and morphology; thickness; Structure of solids and liquids; crystallography; Superlattice; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; GaN; Semipolar; Superlattice; Atomic force microscopy; Stacking faults; Non radiative recombination; Photoluminescence; MOCVD; Gallium nitride; Crystal perfection; III-V compound; Thin films; Temperature measurement; Transmission electron microscopy; Threading dislocation; Superlattices; X-ray diffraction analysis; III-V semiconductors
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2011.09.049

We report on the use of graded superlattices (SLs) for defect reduction in semipolar (112̅2) GaN films, grown by metal-organic chemical vapor deposition. High-resolution x-ray diffraction analysis revealed that there was a great reduction in the full width at half maximum, both on-axis and off-axis, with the SLs. Atomic force microscopy images revealed a significant decrease in slate features which was associated with the basal-plane stacking faults. The transmission electron microscopy images showed that the threading dislocation was greatly reduced after the graded superlattices. Room temperature photoluminescence measurement revealed that the band-edge emission intensity increased with the insertion of the SLs, which suggested reduction in the nonradiative recombination centers.