Epitaxial MgO on GaAs(111) as a buffer layer for <i>z</i>-cut epitaxial lithium niobate

Abstract

The epitaxial system z-lithium niobate on GaAs(111)A and GaAs(111)B has been demonstrated by in situ pulsed laser deposition both with and without intermediate layers of MgO(111). The in-plane epitaxial relationships are LiNbO3[110]∥GaAs[2̄11] and [21̄1̄] indicating the existence of 180° boundaries in the LiNbO3 both with and without the MgO layer, which grows cube-on-cube with the GaAs. Out-of-plane texture is typically 1.0° and 1.2° for the MgO and LiNbO3 layers, respectively. In-plane texture is typically 2.8° and 4.5° for the MgO and LiNbO3 layers, respectively. This epitaxial system may be useful for monolithic electro-optic or frequency doubling applications in conjunction with semiconductor laser diodes.