Single-crystal hexagonal perovskite YAlO3 epitaxially on GaAs(111)A and (001) using atomic layer deposition

摘要

Hexagonal perovskite YAlO3 films were epitaxially grown on both GaAs(001) and GaAs(111)A substrates by utilizing sub-nano-laminated ALD-Y2O3/Al2O3 multilayers with a post-deposition rapid thermal annealing (RTA) to 900 degrees C in He ambience. The c-axis of the YAlO3 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 YAlO3(0004) theta-rocking scan similar to 0.026 degrees, which is close to that of GaAs substrate peak similar to 0.01 degrees, suggesting a high quality epitaxy despite a large lattice mismatch > 6% between the substrates and the films. YAlO3 was found to be single domain as grown on GaAs(111)A but has two rotational domains on GaAs(001). The interfaces between YAlO3 and both GaAs(111)A and GaAs(001) remained atomically abrupt after 900 degrees C RTA. (C) 2017 Elsevier B.V. All rights reserved.