Integration of PLZT and BST family oxides with GaN.

Recent advances in the processing of complex-oxide materials has allowed us to monolithically grow ferroelectrics of lead lanthanum zirconate titanate (PLZT) and barium strontium titanate (BST) systems on a GaN/sapphire struc ture. High quality films of PLZT and BST were grown on GaN/c-Al2O3 in a thi ckness range of 0.3-5 mum by a sol-gel technique. Field-induced birefringen ce, as large as 0.02, was measured from a PLZT layer grown on a buffered Ga N/sapphire structure. UV illumination was found to result in more symmetric al electrooptic hysteresis loop. BST films on GaN demonstrated a low freque ncy dielectric constant of up to 800 with leakage current density as low as 5.5-10(-8) A/cm(2).