Orders of Magnitude Reduction in Threading Dislocations in ZnO Grown on Facet-Controlled GaN

ABSTRACTZnO is grown by chemical vapour deposition on {1 1 -2 2} GaN planes formed by epitaxial layer overgrowth. Window stripes in a SiO2 mask are oriented in the <1 -1 0 0> direction of the GaN film. Triangular GaN ridge are formed during ELO growth by metal organic chemical vapour deposition. A flat (0 0 0 1) ZnO plane is grown on each triangular cross-section ridge and it is found that the ZnO film has dislocation density reduced by two orders of magnitude compared to that of the GaN substrate.