Electronic properties of ferroelectric BaTiO3∕MgO capacitors on GaAs

Thin films of MgO and BaTiO3 were deposited on (001) GaAs substrates using molecular beam epitaxy and pulsed laser deposition, respectively. X-ray diffraction scans indicate crystalline MgO and BaTiO3 thin films with preferential c-axis orientation. Capacitors fabricated from the BaTiO3∕MgO∕GaAs structures demonstrate ferroelectric hysteresis behavior with a remenant polarization of 0.4μC∕cm2. Small-signal capacitance measurements indicate an effective dielectric constant for the BaTiO3∕MgO structure of 45.5ε0. A hysteresis behavior indicative of ferroelectric switching is observed in the capacitance–voltage characteristics with a memory window of approximately 2 V. The observation of ferroelectric behavior in these materials are promising for future multifunctional devices on GaAs.