Two-dimensional halide perovskite lateral epitaxial heterostructures
Two-dimensional halide perovskite lateral epitaxial heterostructures
复制标题
二维卤化物钙钛矿横向外延异质结构
DOI：
10.1038/s41586-020-2219-7
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发表时间：
2020-04-01
期刊：
影响因子：
64.8
通讯作者：
Dou, Letian
中科院分区：
文献类型：
--
作者：
Shi, Enzheng;Yuan, Biao;Dou, Letian
基于氧化物钙钛矿和III-V族、II-VI族和过渡金属二硫属化物半导体的外延异质结构形成了现代电子学和光电子学的基础（1-7）。卤化物钙钛矿-一种新兴的具有期望性能的可调谐半导体家族-对于诸如溶液处理的太阳能电池、发光二极管、检测器和激光器的应用是有吸引力的（8-15）。它们固有的软晶格允许更大的晶格失配容限，使它们有望用于异质结构形成和半导体集成（16，17）。原子尖锐的外延界面是必要的，以提高性能和器件的小型化。然而，卤化物钙钛矿的原子级尖锐异质结构的外延生长尚未实现，这是由于它们的高本征离子迁移率，这导致相互扩散和大的结宽度（18-21），并且由于它们的差的化学稳定性，这导致在后续层的制造期间先前层的分解。因此，了解这种不稳定性的起源并确定抑制离子扩散的有效方法非常重要（22-26）。在这里，我们报告了一种有效的策略，通过引入刚性π共轭有机配体来基本上抑制二维卤化物钙钛矿中的面内离子扩散。我们展示了高度稳定和可调的横向外延异质结构，多异质结构和超晶格。近原子尖锐的界面和外延生长揭示了低剂量像差校正的高分辨率透射电子显微镜。分子动力学模拟证实了在共轭配体存在下，二维钙钛矿的异质结构无序度降低，空位形成能增大。这些发现提供了对卤化物钙钛矿半导体的固定化和稳定化的见解，并展示了复杂的和分子薄的超晶格，器件和集成电路的材料平台。通过使用刚性π共轭配体抑制其异质结构中的离子扩散，提高了二维卤化物钙钛矿的稳定性的外延生长策略被证明，并显示出近原子尖锐的界面。
Epitaxial heterostructures based on oxide perovskites and III-V, II-VI and transition metal dichalcogenide semiconductors form the foundation of modern electronics and optoelectronics(1-7). Halide perovskites-an emerging family of tunable semiconductors with desirable properties-are attractive for applications such as solution-processed solar cells, light-emitting diodes, detectors and lasers(8-15). Their inherently soft crystal lattice allows greater tolerance to lattice mismatch, making them promising for heterostructure formation and semiconductor integration(16,17). Atomically sharp epitaxial interfaces are necessary to improve performance and for device miniaturization. However, epitaxial growth of atomically sharp heterostructures of halide perovskites has not yet been achieved, owing to their high intrinsic ion mobility, which leads to interdiffusion and large junction widths(18-21), and owing to their poor chemical stability, which leads to decomposition of prior layers during the fabrication of subsequent layers. Therefore, understanding the origins of this instability and identifying effective approaches to suppress ion diffusion are of great importance(22-26). Here we report an effective strategy to substantially inhibit in-plane ion diffusion in two-dimensional halide perovskites by incorporating rigid pi-conjugated organic ligands. We demonstrate highly stable and tunable lateral epitaxial heterostructures, multiheterostructures and superlattices. Near-atomically sharp interfaces and epitaxial growth are revealed by low-dose aberration-corrected high-resolution transmission electron microscopy. Molecular dynamics simulations confirm the reduced heterostructure disorder and larger vacancy formation energies of the two-dimensional perovskites in the presence of conjugated ligands. These findings provide insights into the immobilization and stabilization of halide perovskite semiconductors and demonstrate a materials platform for complex and molecularly thin superlattices, devices and integrated circuits.An epitaxial growth strategy that improves the stability of two-dimensional halide perovskites by inhibiting ion diffusion in their heterostructures using rigid pi-conjugated ligands is demonstrated, and shows near-atomically sharp interfaces.