Figure 3
From: Polarity-inverted lateral overgrowth and selective wet-etching and regrowth (PILOSWER) of GaN
SEIs of GaN after regrowth. (a) A tilt view of a regrown GaN film on sapphire, (b) a magnified cross-sectional view of the region marked by a dashed white rectangle in (a). A magnified cross-sectional view of the region marked by a dashed (c) red and (d) blue rectangle in (b), respectively. Green arrows mark the size of openings. Gaps between regrown GaN and sapphire are clearly seen since no nucleation of GaN was possible on the passivated sapphire surface. SEIs of the surface of another regrown sample (e) before and (f) after KOH-etching. Surface roughness is clearly associated with mixed polarity.
