The growth of MgO buffer layers on sapphire for the epitaxy of BaTiO3 optical thin films

摘要: Abstract BaTiO 3 waveguides have been fabricated on r-cut sapphire single crystals using an epitaxial MgO(100) buffer layer. Both films were prepared by pulsed laser deposition (PLD). MgO was grown between 450 and 890°C, deposited at 1000–1050°C. The investigated means of X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), ion channeling (RBS/C), transmission electron microscopy atomic force microscopy. These techniques revealed that the best layers those 750 830°C 2×10 −3 mbar oxygen pressure. characterized a full width half maximum less than 0.5° in XRD rocking curves (Δω) MgO(200) reflection, minimum RBS/C yield (χ min ) ∼5% root-mean-square (rms) roughness 1.7 nm. onto this displayed similar properties: Δω[BaTiO (200)] approximately 0.7°, χ 4–5%, rms 1.0 nm for film 440-nm thickness. relationship found to be [BaTiO (100)//MgO(100)]∼//Al 2 O (1102).