Surface textured zinc oxide films

Both epitaxial and crystallographically fiber-textured ZnO films can exhibit a surface texturing (“cratered”) morphology when grown by pulsed laser deposition at temperatures in the range of 350–750 °C in a background pressure of oxygen. The surface texturing is a consequence of the nucleation of oriented c axis grains that grow geometrically and impinge laterally. It is concluded that the surface texturing is due to nonequilibrium growth, being the result of a competition between the arriving flux, diffusive flux along the surface, and, possibly, concurrent ion etching from the laser-ablated plasma plume. At higher temperatures, no surface texturing occurs, presumably because of concurrent grain growth and more rapid surface smoothing by diffusion.