Synthesis of ZnO nanorods on GaN epitaxial layer and Si (100) substrate using a simple hydrothermal process

One-dimensional ZnO hexagonal nanorod structures were grown vertically on a GaN epitaxial layer and a Si substrate using a simple hydrothermal method. Single crystalline ZnO nanorods were fabricated from aqueous solutions both on the GaN epilayer and Si substrate. X-ray diffraction and field emission scanning electron microscopy revealed ZnO nanorod arrays vertically oriented along the (002) plane on GaN, whereas there were no vertically grown ZnO nanorods on the Si substrate. The photoluminescence spectrum for the GaN–ZnO hetero-structure showed a strong peak in the ultra-violet region and a broad band transition in the yellow emission range. These results demonstrated that the GaN epitaxial layer substrate enables the synthesis of a vertically grown well-aligned ZnO nanostructure array.