LAUSR

Ferroelectric metal-oxide thin films grown on semiconductor substrates are being studied due to their potential applications in non-volatile single transistor memory elements [1]. Epitaxial single-crystalline BaTiO3 (BTO) thin film was successfully grown on polar GaAs substrate with a SrTiO3 (STO) interlayer using molecular beam epitaxy method [2]. The spontaneous polarization of the BTO film was characterized using scanning transmission electron microscope (STEM) along with electron energy-loss spectroscopy (EELS) [3], and the macroscopic ferroelectric switching under coercive electrical biases was measured using piezoresponse force microscopy [4]. However, the microscopic ferroelectric behavior and the switching mechanism at the interfaces have yet to be demonstrated. In this work, we performed an atomic-scale STEM-EELS study of the ferroelectric switching of BTO film on STO-buffered GaAs substrate with in-situ electrical biasing.