Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences (IMR, CAS), Shenyang, 110016, China.
School of Material Science and Engineering, University of Science and Technology of China (USTC), Shenyang, 110016, China.
ACS Nano. 2023 Jul 11;17(13):12347-12357. doi: 10.1021/acsnano.3c01548. Epub 2023 Jun 26.
Controlling the domain evolution is critical both for optimizing ferroelectric properties and for designing functional electronic devices. Here we report an approach of using the Schottky barrier formed at the metal/ferroelectric interface to tailor the self-polarization states of a model ferroelectric thin film heterostructure system SrRuO/(Bi,Sm)FeO. Upon complementary investigations of the piezoresponse force microscopy, electric transport measurements, X-ray photoelectron/absorption spectra, and theoretical studies, we demonstrate that Sm doping changes the concentration and spatial distribution of oxygen vacancies with the tunable host Fermi level which modulates the SrRuO/(Bi,Sm)FeO Schottky barrier and the depolarization field, leading to the evolution of the system from a single domain of downward polarization to polydomain states. Accompanied by such modulation on self-polarization, we further tailor the symmetry of the resistive switching behaviors and achieve a colossal on/off ratio of ∼1.1 × 10 in the corresponding SrRuO/BiFeO/Pt ferroelectric diodes (FDs). In addition, the present FD also exhibits a fast operation speed of ∼30 ns with a potential for sub-nanosecond and an ultralow writing current density of ∼132 A/cm. Our studies provide a way for engineering self-polarization and reveal its strong link to the device performance, facilitating FDs as a competitive memristor candidate used for neuromorphic computing.
控制畴的演化对于优化铁电性能和设计功能电子器件至关重要。在这里，我们报告了一种使用金属/铁电界面形成的肖特基势垒来调整模型铁电薄膜异质结构系统 SrRuO/(Bi,Sm)FeO 自极化状态的方法。通过对压电力显微镜、输运测量、X 射线光电子/吸收谱和理论研究的互补研究，我们证明 Sm 掺杂改变了氧空位的浓度和空间分布，可调谐的宿主费米能级调制了 SrRuO/(Bi,Sm)FeO 肖特基势垒和去极化场，导致系统从单一的下极化畴演变为多畴态。伴随着自极化的这种调制，我们进一步调整了电阻开关行为的对称性，并在相应的 SrRuO/BiFeO/Pt 铁电二极管 (FD) 中实现了高达 ∼1.1×10 的巨大导通/关断比。此外，该 FD 还表现出 ∼30 ns 的快速操作速度，具有亚纳秒的潜力和 ∼132 A/cm 的超低写入电流密度。我们的研究为工程自极化提供了一种方法，并揭示了其与器件性能的紧密联系，促进了 FD 作为用于神经形态计算的有竞争力的忆阻器候选器件的发展。
