Crystal quality improvement of a-plane GaN using epitaxial lateral overgrowth on nanorods

The crystal quality of a-plane GaN films was improved by using epitaxial lateral overgrowth on nano-rod GaN template. The scanning electron microscope images showed the fully coalesced regrowth process completed within only 2 μm thickness. The a-plane GaN films grown on nano-rod template showed superior surface quality and less surface pits. The on-axis and off-axis FWHMs of X-ray rocking curves decreased with the increase in the etching depth of the nano-rod template. TEM analysis revealed that the dislocation density was reduced to around 1.2×109 cm−2 by the nano-rod epitaxial lateral overgrowth. In addition, the photoluminescence intensity of the a-plane GaN was enhanced significantly. These results demonstrated the opportunity of achieving a-plane GaN films with high crystal quality via nano-rod epitaxial lateral overgrowth.