Fig. 3

30 keV cross-sectional BF-STEM images of the epitaxial GaN layer and corresponding TED pattern for different two-beam conditions a, d g_(000–2), b, e g_(1–210), and c, f g_(1–100). ZB and strongly excited Bragg reflections are marked in d–f. The settings of the α- and β-tilt angle are given in the BF-STEM images. Scale bars in a and d apply to all BF-STEM images and diffraction patterns, respectively. Dark spot-like regions result from contamination that occurred during sample orientation by acquiring diffraction patterns with a high beam current