摘要
Hexagonal perovskite YAlO <sub>3</sub> films were epitaxially grown on both GaAs(001) and GaAs(111)A substrates by utilizing sub-nano-laminated ALD-Y <sub>2</sub> O <sub>3</sub> /Al <sub>2</sub> O <sub>3</sub> multilayers with a post-deposition rapid thermal annealing (RTA) to 900 °C in He ambience. The c-axis of the YAlO <sub>3</sub> films was aligned along the surface normal of GaAs(001) and GaAs(111)A substrates. Excellent crystallinity was evidenced by the pronounced thickness fringes and the narrow peak width of YAlO <sub>3</sub> (0004) θ-rocking scan ~ 0.026°, which is close to that of GaAs substrate peak ~ 0.01°, suggesting a high quality epitaxy despite a large lattice mismatch > 6% between the substrates and the films. YAlO <sub>3</sub> was found to be single domain as grown on GaAs(111)A but has two rotational domains on GaAs(001). The interfaces between YAlO <sub>3</sub> and both GaAs(111)A and GaAs(001) remained atomically abrupt after 900 °C RTA.