Defect-mediated surface morphology of nonpolar m-plane GaN

The role of extended defects in determining the atomic scale surface morphology of nonpolar {11¯00} m-plane gallium nitride has been elucidated. The heteroepitaxially grown m-GaN films are commonly reported to yield striated surface morphologies (slate morphology) correlated with their high densities of basal plane stacking faults. Here, the growth window was explored to allow nonslate morphologies for hydride vapor phase epitaxy. Lateral epitaxial overgrowth was then utilized to produce m-GaN films with three regimes of different extended defect contents. Elimination of stacking faults from the m-GaN yielded step-flow features with an average step height of 4–7 ML even for slate morphology growth conditions.