二维/三维有机-无机钙钛矿异质结构及其阻变存储器研究

Organic-inorganic perovskite is emerging rapidly as one type of electronic material in recent years. Due to the diversity of functions and structures with the simple fabrication process, organic-inorganic perovskite is very suitable for resistive random access memory devices and has great application potential in information storage and neuromorphic computing. However, the material stability problem is always a very important issue for perovskite, and how to improve the stability is the focus of the perovskite research society. The two-dimension (2d) perovskite has the excellent material stability, while the three-dimension (3d) perovskite has the excellent electrical properties. By combining the 2d and 3d perovskites, it has the potential to further improve device performance and stability. However, there are few reports about the resistive memory devices with the combining perovskites. This project aims to investigate the resistive memory devices with the 2d/3d perovskite heterojunction structure, and focuses on the fundamental problems such as growth mechanism of the 2d/3d perovskite heterojunction, the interface control method of the 2d/3d perovskite heterojunction and the physical storage mechanism of the heterojunction resistive memory devices. By investigating the growth of 2d/3d perovskite heterojunction, fabricating the memory devices, characterizing the material and device properties, and researching the device conducting mechanism, we try to realize the 2d/3d perovskite heterojunction with the excellent interface, obtain the optimized material growth parameters, master the key process to fabricate the perovskite resistive memory devices, clarify the effects of heterojunction on the material and device stability, and grasp the conduction mechanism of perovskite resistive memory devices. Through above work, it is believed that the improvement of device performance and stability could be obtained for the perovskite resistive memory devices with 2d/3d perovskite heterojunction structures.

有机-无机钙钛矿材料是近年来发展最为迅速的新兴电子材料之一，其结构和性能多样，制备工艺简单，非常适于阻变存储器件，在信息存储和仿神经计算等领域应用潜力巨大。然而，钙钛矿材料存在稳定性问题，如何提高稳定性一直是人们关注的焦点。二维（2d）钙钛矿材料的稳定性高，而三维（3d）钙钛矿材料的电学特性好，结合2D/3D钙钛矿材料优点有望进一步提高器件性能和稳定性，但相关阻变存储器研究鲜有报道。本项目拟开展2D/3D钙钛矿异质结阻变存储器研究，围绕2D/3D钙钛矿异质结形成机理、异质界面控制方法、异质结阻变存储特性及物理机制等问题，从异质结生长、器件制备、材料及电学特性表征、导电机理研究等方面开展工作，实现具有良好界面的2D/3D钙钛矿异质结，获取优化的材料生长参数，掌握阻变存储器关键工艺，阐明异质结对材料和器件稳定性的影响，获得阻变存储器导电机制，最终实现钙钛矿存储器性能和稳定性的提升。

有机-无机钙钛矿材料是近年来发展最为迅速的新兴电子材料之一，其结构和性能多样，制备工艺简单，非常适于阻变存储器件，在信息存储和仿神经计算等领域应用潜力巨大。然而，钙钛矿材料存在稳定性问题，如何提高稳定性一直是人们关注的焦点。二维（2d）钙钛矿材料的稳定性高，而三维（3d）钙钛矿材料的电学特性好，结合2D/3D钙钛矿材料优点有望进一步提高器件性能和稳定性，但相关阻变存储器研究鲜有报道。本课题通过薄膜制备、器件制备、工艺优化、电学特性表征、导电机理研究等方法和途径，开展了钙钛矿薄膜特生长加工与物性测试表征、钙钛矿薄膜的组分调控和全无机钙钛矿薄膜材料特性、全无机钙钛矿器件应用以及钙钛矿阻变存储器件性能优化的研究工作。在钙钛矿薄膜特性物性测试表征方面：开展溶剂氛围退火工作优化了钙钛矿结晶质量，对比IPA/DMSO、IPA、IPA/DMF溶剂气氛退火对薄膜结晶质量的影响，得出了IPA/DMF是较为理想的气氛溶剂，并引入PEAI和DMF作为添加剂，展示了一种通过调制扩散钝化来提高2D/3D钙钛矿薄膜的效率和稳定性的新颖策略；在钙钛矿组分调控和材料特性方面：我们在钙钛矿组分中A位引入了Cs和FA，X位引入了Br，优化了FA/Cs和I/Br的比例，最终确定以FA0.15Cs0.85Pb(I0.73Br0.27)3组分作为钙钛矿有效层材料，并且首次证明了通过简单控制其前驱体化学计量比，可以有效地固化一步旋涂CsPbIBr2膜中不良的自掺杂现象；在器件应用以及阻变存储器件性能优化方面：我们提出了一种基于中间相卤素交换反应的简便方法来制备质量优异且厚度可调的CsPbBr3薄膜，基于此制备了光电探测器件研究其电学特性，光电探测器件响应度为0.35 A/W，比探测率1.94×1013 Jones，这些性能超出了大多数类似结构的CsPbBr3光电探测器，通过优化电极及器件结构制备了阻变存储器件，优化后的阻变存储器操作电压＜1 V，在10000 s测试及200次循环后保持了1000的开关比。研究成果基本达到了原定研究目标，所取得的研究成果也将为进一步优化钙钛矿阻变存储器件提供丰厚的研究基础。