Epitaxial deposition of BaTiO3 on TiO2 buffered GaAs(001) substrate

Ferroelectric BaTiO3 thin films were epitaxially grown on rutile-TiO2 buffered GaAs(001) substrates by pulsed laser deposition system. The in-plane relationship of this heterostructure is 〈110〉BaTiO3//〈001〉TiO2//〈110〉GaAs and the out-plane relationship is BaTiO3(110)//TiO2(110)//GaAs(001). The surface of BaTiO3 is flat and the interfaces between each layer are clear. The oxygen vacancies were eliminated by ex-situ annealing in adequate O2. In short, a highly (110)-oriented BaTiO3 thin film was grown on TiO2 buffered GaAs (001) substrate with excellent electrical and structural properties. The BaTiO3(150 nm)/TiO2(40 nm)/GaAs system demonstrates hysteresis loops with a remnant polarization of 2.6 μC/cm2 and a small leakage current density of 1 × 10− 6 A/cm2 both at 300 kV/cm.