Vats Nilesh, Wang Yi, Sen Suman, Szilagyi Sven, Ochner Hannah, Abb Sabine, Burghard Marko, Sigle Wilfried, Kern Klaus, van Aken Peter A, Rauschenbach Stephan
Max Planck Institute for Solid State Research, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
Institut de Physique de la Matière Condensée, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland.
ACS Nano. 2020 Apr 28;14(4):4626-4635. doi: 10.1021/acsnano.9b10053. Epub 2020 Apr 17.
Formation and characterization of low-dimensional nanostructures is crucial for controlling the properties of two-dimensional (2D) materials such as graphene. Here, we study the structure of low-dimensional adsorbates of cesium iodide (CsI) on free-standing graphene using aberration-corrected transmission electron microscopy at atomic resolution. CsI is deposited onto graphene as charged clusters by electrospray ion-beam deposition. The interaction with the electron beam forms two-dimensional CsI crystals only on bilayer graphene, while CsI clusters consisting of 4, 6, 7, and 8 ions are exclusively observed on single-layer graphene. Chemical characterization by electron energy-loss spectroscopy imaging and precise structural measurements evidence the possible influence of charge transfer on the structure formation of the CsI clusters and layers, leading to different distances of the Cs and I to the graphene.
低维纳米结构的形成与表征对于控制二维（2D）材料（如石墨烯）的性质至关重要。在此，我们使用原子分辨率的像差校正透射电子显微镜研究了碘化铯（CsI）在独立石墨烯上的低维吸附物结构。通过电喷雾离子束沉积将CsI作为带电团簇沉积到石墨烯上。与电子束的相互作用仅在双层石墨烯上形成二维CsI晶体，而在单层石墨烯上仅观察到由4、6、7和8个离子组成的CsI团簇。通过电子能量损失谱成像进行的化学表征和精确的结构测量证明了电荷转移对CsI团簇和层结构形成的可能影响，导致Cs和I到石墨烯的距离不同。
