Investigating stacking faults in nonpolar gallium nitride films using X-ray diffraction

Nonpolar (11–20) GaN films with different basal-plane stacking fault (BSF) densities (determined using transmission electron microscopy) were investigated using X-ray diffraction. Diffuse streaking from I 1 and I 2 BSFs was observed in reciprocal space maps of the 10–10 and 20–20 reflections. X-ray calibration curves for BSF density determination can be plotted using the diffusely scattered intensity of open detector 10–10 or 20–20 ω-scans measured at a fixed, large separation from the peak maximum. However, ab initio determination of stacking fault densities is not possible due to additional broadening from other defects. Similarly, ω-scan peak widths are poor indicators of BSF densities.