Understanding the interaction between energetic ions and freestanding graphene towards practical 2D perforation
Understanding the interaction between energetic ions and freestanding graphene towards practical 2D perforation
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DOI：
10.1039/c6nr00154h
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发表时间：
2016-01-01
期刊：
影响因子：
6.7
通讯作者：
Park, Hyung Gyu
中科院分区：
文献类型：
--
作者：
Buchheim, Jakob;Wyss, Roman M.;Park, Hyung Gyu
我们从实验和理论上报道了高能离子轰击下独立石墨烯的行为，研究了通过聚焦离子束技术大规模图案化具有纳米尺寸特征的独立石墨烯的能力。通过聚焦离子束技术提供的对He+和Ga+照射的精确控制使得能够研究高能粒子和在没有支撑的情况下悬浮的石墨烯的相互作用，并且允许确定2D晶格的溅射产率。我们发现了一个很强的依赖性的2D溅射产率上的物种和入射离子束的动能。独立式石墨烯在高能量（10-30 keV）下显示出对He+的材料半透明性，允许>97%的He+颗粒通过而不产生破坏性的晶格空位。相比之下，大Ga+离子（5-30 keV）更经常地与石墨烯晶格碰撞以赋予类似于50%的显著更高的溅射产率。应用于单层和少层石墨烯的二元碰撞理论可以成功地阐明这种碰撞机制，与实验非常一致。拉曼光谱分析证实了大部分He+离子穿过石墨烯而没有太多损坏晶格，而几个碰撞离子产生单个空位缺陷。对高能粒子和悬浮石墨烯之间相互作用的物理理解实际上可以通过设计在2D材料上产生前所未有的小特征的可再现和有效的图案生成，这表现在我们对亚5 nm孔阵列的穿孔上。这种独立的2D晶格的纳米级精确图案化的能力显示了聚焦离子束技术对用于器件制造和集成的2D材料处理的实用性。
We report experimentally and theoretically the behavior of freestanding graphene subjected to bombardment of energetic ions, investigating the capability of large-scale patterning of freestanding graphene with nanometer sized features by focused ion beam technology. A precise control over the He+ and Ga+ irradiation offered by focused ion beam techniques enables investigating the interaction of the energetic particles and graphene suspended with no support and allows determining sputter yields of the 2D lattice. We found a strong dependency of the 2D sputter yield on the species and kinetic energy of the incident ion beams. Freestanding graphene shows material semi-transparency to He+ at high energies (10-30 keV) allowing the passage of >97% He+ particles without creating destructive lattice vacancy. Large Ga+ ions (5-30 keV), in contrast, collide far more often with the graphene lattice to impart a significantly higher sputter yield of similar to 50%. Binary collision theory applied to monolayer and few-layer graphene can successfully elucidate this collision mechanism, in great agreement with experiments. Raman spectroscopy analysis corroborates the passage of a large fraction of He+ ions across graphene without much damaging the lattice whereas several colliding ions create single vacancy defects. Physical understanding of the interaction between energetic particles and suspended graphene can practically lead to reproducible and efficient pattern generation of unprecedentedly small features on 2D materials by design, manifested by our perforation of sub-5 nm pore arrays. This capability of nanometer-scale precision patterning of freestanding 2D lattices shows the practical applicability of focused ion beam technology to 2D material processing for device fabrication and integration.