Fig. 1

The experimental ω − φ 2D intensity scattering maps of a GaN (0002) and b SL (0002) reflections for S20. The red curves are the fitted offset angles of α ^GaN and α ^SL with Eq. (1). The subtracted α ^GaN − α ^SL curve along with the φ-scan for GaN \( \left(10\overline{1}2\right) \) reflection is shown in c. The inset demonstrates the misorientation angles relative to the surface normal direction