Phase development and crystallization of CuAlO₂ thin films prepared by pulsed laser deposition

A polycrystalline CuAlO₂ single-phase target was fabricated by the conventional solid-state reaction route using Cu₂O and Al₂O₃. Thin films of CuAlO₂ were deposited by a pulsed laser deposition process on sapphire substrates at different temperatures. Then, post-annealing was followed at different conditions, and the phase development process of the films was examined. As grown thin films in the temperature range of 450-650 °C were amorphous. The c-axis oriented single phase of CuAlO₂ thin films were obtained when the films were post-annealed at 1100 °C in air after growing at 650 °C. Phi-scan of the film clearly showed 12 peaks, each of which are positioned at intervals of 30°. This is thought to be caused by the rhombohedral structured CuAlO₂ thin film growing in the states of 30° tilt during the annealing process. Hall effect analysis of the film was carried out.