López Luis E Parra, Rosławska Anna, Scheurer Fabrice, Berciaud Stéphane, Schull Guillaume
Université de Strasbourg, CNRS, Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504, Strasbourg, France.
Nat Mater. 2023 Apr;22(4):482-488. doi: 10.1038/s41563-023-01494-4. Epub 2023 Mar 16.
The electronic and optical properties of van der Waals heterostructures are strongly influenced by the structuration and homogeneity of their nano- and atomic-scale environments. Unravelling this intimate structure-property relationship is a key challenge that requires methods capable of addressing the light-matter interactions in van der Waals materials with ultimate spatial resolution. Here we use a low-temperature scanning tunnelling microscope to probe-with atomic-scale resolution-the excitonic luminescence of a van der Waals heterostructure, made of a transition metal dichalcogenide monolayer stacked onto a few-layer graphene flake supported by a Au(111) substrate. Sharp emission lines arising from neutral, charged and localized excitons are reported. Their intensities and emission energies vary as a function of the nanoscale topography of the van der Waals heterostructure, explaining the variability of the emission properties observed with diffraction-limited approaches. Our work paves the way towards understanding and controlling optoelectronic phenomena in moiré superlattices with atomic-scale resolution.
范德华异质结构的电学和光学性质受到其纳米和原子尺度环境的结构和均匀性的强烈影响。揭示这种紧密的结构-性质关系是一项关键挑战，需要能够以最终空间分辨率解决范德华材料中光与物质相互作用的方法。在这里，我们使用低温扫描隧道显微镜以原子尺度分辨率探测由堆叠在由Au(111)衬底支撑的几层石墨烯薄片上的过渡金属二硫属化物单层制成的范德华异质结构的激子发光。报道了由中性、带电和局域激子产生的尖锐发射线。它们的强度和发射能量随范德华异质结构的纳米尺度形貌而变化，解释了用衍射极限方法观察到的发射特性的变化。我们的工作为以原子尺度分辨率理解和控制莫尔超晶格中的光电现象铺平了道路。
