Figure 1: Schematic of cross-sectional view of the growing GaN layer: (a) stage I – inclination of TDs during growth; dashed line represents partially coalesced islands with TDs terminating at bottoms of grooves; at the interface TDs close up and form a misfit dislocation (MD); (b) stage I – optional filling of grooves with mask material to enhance the probability for TD inclination; (c) stage II – regrowth step with flattened surface and TD reactions.