EPITAXIAL MGO ON GAAS(111) AS A BUFFER LAYER FOR Z-CUT EPITAXIAL LITHIUM-NIOBATE

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] parallel-to GaAs[211BAR] and [211BAR] indicating the existence of 180-degrees 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-degrees and 1.2-degrees for the MgO and LiNbO3 layers, respectively. In-plane texture is typically 2.8-degrees and 4.5-degrees 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.