Research On The Information Storage Device Based On BiFeO₃ Thin Film Heterostructures

The multiferroic BiFeO₃?BFO? has obvious birefringence dispersion properties, the low-dimensional structure and interface properties of BFO thin film heterostructures will make its photophysical properties more abundant, so it is significant to study the electro-optical effects of BFO thin films and its heterostructures, as well as exploring its application in information storage devices.In this dissertation, the ele ctro-optical properties of BFO thin films and its heterostructures have been studied, and an information storage device based on the electro-optical effect of BiFeO₃/Au heterostructures is designed. Also, Au/BiFeO₃/LaAlO₃ heterostructures are prepared and its electro-optical effects have been investigated experimentally. The main contents are as follows:1. The current major information storage methods are overviewed. The electro-optical crystal and electro-optic effect are summarized, indicating the advantages of the electro-optical properties of BFO and its value in information storage devices. The background and significance of this dissertation are introduced.2. BiFeO₃/metal heterostructures are designed, the spectral properties and electro-optical modulation effect of BiFeO₃/Au and BiFeO₃/Pt heterostructures are simulated, visible resonance absorption phenomena and electro-optical modulation characteristics are found, the affections of various parameters on the heterostructures resonance absorption are analyzed.3. An 'electrical-writing, optical-reading' information storage device is designed based on significant electro-optical modulation characteristics of BiFeO₃/Au heterostructures, combining the advantages of information ?written' by ferroelectric storage and ?readout' by optical storage. The design ideas, principles and structures of information storage device are proposed, and its advantages and implementation methods are summarized. The method of information ?written' based on ITO?indium-tin oxide? electrodes is also designed.4. BiFeO₃/LaAlO₃ heterostructures are prepared by Pulsed Laser Deposition, and its optical characteristics are studied by Spectroscopic Ellipsometry measurements. Au/BiFeO₃/LaAlO₃ heterostructures are designed and prepared with the interdigitated Au electrode prepared by Lithography Technologies and Magnetron Sputtering, and its electro-optical effect is found and studied when voltage is applied to the BFO film.