Hybrid MBE of BaTiO₃ membranes with a growth window

BaTiO₃ (BTO) membranes are of growing interest for their intrinsic ferroelectric properties and flexibility but fabricating them via molecular beam epitaxy (MBE) faces challenges, particularly in achieving stoichiometry, atomical layer control and ferroelectric characteristics. In this talk, we present a detailed hybrid MBE growth and characterization study demonstrating single crystalline, epitaxial BTO films using a SrO sacrificial layer. By optimizing the titanium tetraisopropoxide (TTIP)/Ba flux ratio, the films exhibit a self-regulated growth window with automatic stoichiometry control, confirmed by X-ray diffraction. BTO membranes were achieved by dissolving sacrificial layer in DI water. Further structural and ferroelectric characterizations, including Raman spectroscopy, piezoresponse force microscopy (PFM) and polarization-electric field (PE) loop, validate the BTO membranes' ferroelectric properties. Metal-insulator-metal devices using BTO membranes (Pt/BTO/Pt) show threshold switching behavior, highlighting potential for applications in artificial neurons and other novel devices.