X-ray di!raction characterization of epitaxial zinc-blende GaN "lms on a miscut GaAs(0 0 1) substrates using the hydride vapor-phase epitaxy method

In this study, cubic GaN epitaxial "lms are grown on a 23miscut GaAs(0 0 1) substrate by hydride vapor-phase epitaxy reactor with a low-temperature GaN bu!er layer before the growth of the GaN epitaxy "lm. X-ray di!raction spectra reveal that the epitaxial "lm contains most of the zinc-blende GaN with a few percent of wurtzite GaN also embedded in the "lm. The crystalline coherence length of the zinc-blende GaN is 30 nm and the rocking curve width is 4.83. In addition, in the /-scan, are found, two small peaks in two-fold symmetry which did not correspond to the substrate orientation relation of GaN(0 0 1)EGaAs(0 0 1) and GaN(0 1 0)EGaAs(0 1 0). These two small peaks were grown along the miscut direction of the substrate. Photoluminescence spectra con"rm that a cubic GaN edge emission peak appears at 388 nm as well as a strong yellow emission at 500 nm region. ( 1999 Elsevier Science B.V. All rights reserved.