Self-regulated in-plane polarity of [1 1 ̄ 00] -oriented GaN domains coalesced from twins grown on a SiO₂-patterned m -plane sapphire substrate

In-plane polarity of [11̄00]-oriented GaN domains coalesced from twins grown on a SiO₂-patterned m-plane sapphire substrate was observed to be self-regulated in such a way that basal faces of coalesced domains were mainly found to have the (0001̄) polarity only. This self-regulation behavior of in-plane polarity was explained by a computational simulation of plan-view surface morphology evolution during coalescence of twins. Based on a computational simulation, asymmetrically suppressed growth rates of twins near a SiO₂ pattern were proposed to be responsible for the survival of the slower growing (0001̄) basal faces instead of the faster growing (0001) basal faces during coalescence of twins.