Figure 6: XRD peak width of an optimized zincblende GaN sample displayed in a traditional Williamson-Hall plot with fits for Lorentzian (n = 1) and Gaussian shape peaks (n = 2).

Figure 7: Extrapolated peak width β_hkl ×|Q_hkl| in reciprocal space as a function of polar angle Chi and scattering vector magnitude |Q_hkl| estimated from a series of skew-symmetric ω-scans.

Figure 8: Decrease of the XRD ω-linewidth (FWHM) of the 002 reflection with increasing film thickness for oriented zincblende GaN grown on 3C-SiC at Cambridge University.

Figure 9: An example for a XRD wafer bow analysis of a 4'' 3C-SiC/Si template showing the shift of the maximum of ω-scans at different positions on the wafer.