Effect of post-annealing time on the properties of sputtered Al-doped ZnO thin films

Al doped ZnO (AZO) thin films prepared by RF magnetron sputtering were annealed in rapid thermal annealing system under various post-annealing times. The effect of post-annealing time on the structural, optical, and electrical properties of AZO film was investigated, systematically. As the post-annealing time elongated, the electrical resistivity was improved due to an increase in the carrier concentration and the mobility. X-ray photoelectron spectroscopy showed that the long post-annealing time increased the oxygen vacancy and decreased the surface bonding caused by the O 2 absorption on surface, resulting in increase of the carrier concentration and the mobility. Therefore, the post-annealing time plays an important role in determining the nature of bonding in AZO thin films and is a powerful method to obtain better electrical properties.