Liang Qingrong, Zheng Guozhong, Fan Shuaiwei, Yang Liu, Zheng Shoujun
Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, China.
School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710062, China.
Adv Mater. 2025 Feb;37(7):e2416117. doi: 10.1002/adma.202416117. Epub 2024 Dec 20.
Through the stacking technique of 2D materials, the interfacial polarization can be switched by an interlayer sliding, known as sliding ferroelectricity, which is advantageous in ultra-thin thickness, high switching speed, and high fatigue resistance. However, uncovering the relationship between the sliding path and the polarization state in rhombohedral-stacked materials remains a challenge, which is the key to 2D sliding ferroelectricity. Here, layer-dependent multidirectional sliding ferroelectricity in rhombohedral-stacked InSe (γ-InSe) is reported via dual-frequency resonance tracking piezoresponse force microscopy and conductive atomic force microscopy. The graphene/γ-InSe/graphene tunneling device exhibits a tunable bulk photovoltaic effect with a photovoltaic current density of ≈15 mA cm due to multiple polarization states. The generation of dome-like domain walls is observed experimentally, which is attributed to the multidirectional sliding-induced domains based on the theoretical calculations. Furthermore, the ferroelectric polarization in γ-InSe ensures that the tunneling device has a high photo responsivity of ≈255 A W and a fast response time for real-time imaging. The work not only provides insights into the multidirectional sliding ferroelectricity of rhombohedral-stacked 2D materials but also highlights their potential for tunable photovoltaics and imaging applications.
通过二维材料的堆叠技术，界面极化可通过层间滑动来切换，即所谓的滑动铁电性，这在超薄厚度、高切换速度和高抗疲劳性方面具有优势。然而，揭示菱面体堆叠材料中滑动路径与极化状态之间的关系仍然是一个挑战，这是二维滑动铁电性的关键。在此，通过双频共振跟踪压电力显微镜和导电原子力显微镜，报道了菱面体堆叠的InSe（γ-InSe）中层依赖的多向滑动铁电性。由于多种极化状态，石墨烯/γ-InSe/石墨烯隧道器件表现出可调的体光伏效应，光伏电流密度约为15 mA/cm²。实验观察到圆顶状畴壁的产生，基于理论计算，这归因于多向滑动诱导的畴。此外，γ-InSe中的铁电极化确保隧道器件具有约255 A/W的高光响应率和用于实时成像的快速响应时间。这项工作不仅深入了解了菱面体堆叠二维材料的多向滑动铁电性，还突出了它们在可调谐光伏和成像应用方面的潜力。
