The effect of heating rate on the structural and electrical properties of sol–gel derived Al-doped ZnO films

Al-doped ZnO (AZO) films are prepared by sol–gel method with a proper annealing procedure. For the first time, we find that the heating rate which is normally neglected during the post annealing process plays a significant role in improving AZO properties. The AZO film with nanorod structure is obtained by using a rapid heating rate. The AZO nanorods can provide a faster conduction pathway for charge transport due to the high crystal quality and thus enhance the conductivity of the film significantly. After hydrogen treatment, the AZO nanorod film exhibits a minimum resistivity of 1.4 × 10−3 Ω cm. This approach to the preparation of AZO nanorods by a simple rapid annealing process may be helpful for the development of sol–gel-derived TCO films.