Zinc oxide microtowers by vapor phase homoepitaxial regrowth

The realization of simultaneous axial and radial epitaxies by growing ZnO microtowers through a regrowth technique of repeating the same growth cycle inside a well controlled tube furnace system was studied. Commercial ZnO powder was used a source material. The temperature of the crystal growth region was carefully measured using an external thermal couple, in order to understand the interplay between growth temperature and product morphology. High Resolution TEM (HRTEM) imagining reveals that the surface of the pedion is very clean and abrupt on an atomic scale and atomic steps can also be identified. The needle ending whiskers can be regarded as a variant of the pyramid-ending whiskers formed by growing a straight ZnO nano-or microrod directly on top vertexes of the dihexagonal pyramid-ending whiskers. The simultaneous axial and radial homoepitaxies can be fully realized in growing artificial ZnO crystalline microtowers.