Figure 1.

AFM image of the surface of AlN layer grown on NPSS substrate in a scanned area of a) 10 × 10 µm² (scale bar: 14 nm) and b) 2 × 2 µm² (scale bar: 0.6 nm) with an RMS roughness of about 0.09 nm. Cross‐sectional dark‐field STEM images under two‐beam conditions for AlN grown on NPSS with c) g = [0002], and d) g = $[11\overline{2}0]$. Based on the standard Burgers vector analysis using invisibility criterion g · b = 0, the screw‐type and edge‐type dislocation lines are observed in (c) and (d), respectively.