Sol-gel derived transparent conducting ZnO:Al thin films: Effect of crystallite orientation on conductivity and self-assembled network texture

The effect of crystallite orientation on the conductivity of ZnO:Al (AZO) thin films has been investigated by means of sol-gel technique. The sol composition has a pronounced influence on the crystallite orientation and size of the AZO thin films. A lower sheet resistance of the films with high c-axis orientation is attributed to the improved packing density caused by perfect crystallite alignment rather than an anisotropic effect. Network texture with uniformly protruding “walls” arranged randomly on the film surface is formed at a higher Al content of 5.0 at.%. A further optimization of film resistivity and texture may find an application of sol-gel AZO thin films in thin film solar cells.