Electrical properties of ferroelectric BaTiO_3 thin film on SrTiO_3 buffered GaAs by laser molecular beam epitaxy

摘要

Ferroelectric BaTiO_3 thin films were epitaxially grown on (001) GaAs substrate using SrTiO_3 as a buffer layer by laser molecular beam epitaxy. The perovskite SrTiO_3 buffer layer present a body centered cubic structure by formation of an interfacial layer with the [100]SrTiO_3||[110]GaAs in-plane relationship. Thereupon, a highly c-oriented BaTiO_3 thin film was grown on SrTiO_3/GaAs in a layer by layer mode. Enhanced electrical properties of the heteroepitaxial structure were demonstrated. The BaTiO_3(150 nm)/SrTiO_3/GaAs system demonstrates hysteresis loops with a remnant polarization of 2.5 μC/cm~2 at 600 kV/cm and a small leakage current density of 2.9 × 10~(-7) A/cm~2 at 200 kV/cm.