中能离子束在二维层状纳米材料中的散射机制研究

Two-dimensional (2D) materials represented by graphene have unique 2D layered structure, exhibiting excellent physical, chemical, electronic and optical properties enabling a wide spectra of applications. Ion beam technology has important applications in two-dimensional materials, such as ion implantation and modification, irradiation study and material analysis. Compared to traditional materials, 2D materials introduces some special quantum effects when interacting with incident ions, which leads to different physical mechanism of the interaction. The lack of understanding of the interaction mechanism between ions and two-dimensional materials has limited the application of ion beam technology in the field of two-dimensional materials. This project intends to study the interaction mechanism between various of ions at energies of 100 keV - 400 keV and 2D materials, such us graphene, MoS2 with a tandem accelerator. Experiments will be performed to obtain significant data such as scattering cross sections, energy loss, and based on the experiment results, the ion-2D crystal interaction model and theories will been established, laying scientific basic for ion beam technology application in the field of 2D materials.

以石墨烯为代表的二维材料具有独特的二维层状结构，表现出优异的物理、化学、电子和光学性能，在众多领域具有应用潜力。离子束技术在二维材料中有着重要的应用，如离子注入改性、辐照效应研究、材料分析等。相比于传统材料，二维材料引入了一些特殊的量子效应，这将导致离子散射机制发生变化。对离子束与二维材料的相互作用机制认知的缺乏限制了离子束技术在二维材料领域更好的应用。本项目以串列加速器为平台，研究100keV~400keV能段内多种离子与石墨烯，MoS2的作用机制，测定散射截面、能损等数据，以此为基础完善相关基础理论，为离子束技术在二维材料领域的应用奠定科学基础。

本项目开展了离子束与二维材料相互作用研究，重点针对离子透射二维材料的能量损失和电荷交换测量以及离子辐照二维材料两部分开展工作。采用静电分析器对透射离子的电荷态分布和能量损失进行测量研究，采用透射电子显微镜观测离子辐照实验结果。在能量45keVAr15+离子透射多层石墨烯（5层、10层）的实验中，通过分析透射离子能量和电荷态分布发现，透射离子+3~+1价态的峰位上出现了离子和石墨烯材料的电荷交换峰，伴随有明显的能量损失，离子能损随出射电荷态的下降呈上升趋势。在能量90keV的Xe30+离子的辐照下，单层和两层石墨烯无辐照痕迹，但5层、6~8层和10层石墨烯出现了辐照非晶化区域，非晶化区域呈圆形，平均直径在50nm~100nm左右，并在非晶化区域和晶体区域的交界有凸起现象。