Microstructure of ZnO films synthesized on Mg[Al.sub.2][O.sub.4] from low-temperature aqueous solution: growth and post-annealing

The microstructure of ZnO films synthesized from low-temperature (90°C) aqueous solution on (111) Mg[Al.sub.2][O.sub.4] single crystal substrates was characterized by X-ray diffraction, high-resolution scanning electron microscopy, conventional and high-resolution transmission electron microscopy. To examine the thermally activated microstructural evolution of the ZnO, both as-deposited and annealed films were characterized. The ZnO films were confirmed to have a ZnO [1010](0001)k Mg[Al.sub.2][O.sub.4] [011 ](111) orientation relationship, with Zn polarity normal to the surface. Despite their highly oriented nature, the ZnO films have a columnar grain structure with low-angle (