Fig. 5: Strain field relaxation through ELOG method.

a SEM image of the cross-section of ELO GaN. b Misfit biaxial strain distributions in ELO GaN by AES. c Cross-sectional TEM micrograph in [11\(\overline 2\)0] orientation from a selectively grown GaN stripe revealing the coalescence and change of the direction of dislocation lines. d Cross-sectional SEM micrograph of a fully coalesced 20 μm-thick AlN film grown by migration enhanced lateral epitaxial overgrowth technique. e XRCs of (0002) and (10\(\overline 1\)2) diffractions for the AlN films grown on the nanopatterned substrate. f 3D AFM image for the surface morphology of the pyramidal patterned sapphire substrate. Figures reproduced from a and b ref. ⁸¹, © 2005 AIP Publishing; c ref. ⁷⁸, © 1997 AIP Publishing; d and e ref. ⁸⁴, © 2013 AIP Publishing; f ref. ⁸⁵, © 2019 AIP Publishing