Phase development and crystallization of CuAlO_2 thin films prepared by pulsed laser deposition

摘要

A polycrystalline CuAlO_2 single-phase target was fabricated by the conventional solid-state reaction route using Cu_2O and Al_2O_3. Thin films of CuAlO_2 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 deg C were amorphous. The c-axis oriented single phase of CuAlO_2 thin films were obtained when the films were post-annealed at 1100 deg C in air after growing at 650 deg C. Phi-scan of the film clearly showed 12 peaks, each of which are positioned at intervals of 30 deg. This is thought to be caused by ihe rhombohedral structured CuAlO_2 thin film growing in the states of 30° tilt during the annealing process. Hall effect analysis of the film was carried out.