美研发新方法能制作完美边缘与单分子层石墨烯

在硅芯片设计规则往原子等级迈进的过程中，石墨烯(graphene)被认为可以清除许多障碍，能制作尺寸更小、性能更好的纯碳组件。但有一个问题在于，在纳米等级，组件规格必须要达到原子精度(atomic accuracy)，包括接近完美边缘(perfect edges)与单分子层(monolayers)。

美国能源部所属的橡树岭国家实验室(Oak Ridge National Laboratory)正在打造一套可制作完美石墨烯薄片的工具；该实验室最近还发现，电子辐射(electron radiation)能避免单分子层之间的连结。研究人员利用超级计算机仿真了采用量子分子动力(quantum molecular dynamic)制作石墨烯的过程，并宣称已开发出能制作完美边缘与单分子层石墨烯的全新方法。

去年该研究团队发表了一种称为“焦耳加热(Joule heating)”的方法，采用电流将石墨烯边缘修整至完美，但所付出的代价是会产生让单分子层链接的结构性回路(structural loops)。在超级计算机仿真中，通过采用量子分子动力做为中间步骤，研究人员开发出了一种全新的边缘形成(edge-formation)制程，而且已经能控制该步骤、优化石墨烯生产制程。

该研究团队并表示，在该边缘形成制程中采用电子辐射，就能避免在制作过程中产生让石墨烯单分子层连结的回路。

点击进入参考原文：Graphene fabrication gets a boost, by R. Colin Johnson

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Graphene fabrication gets a boost

by R. Colin Johnson

Graphene, which promises to solve many problems as silicon design rules approach the atomic scale, performs better when these pure carbon devices are made smaller. The catch is that at the nanoscale level, features must have atomic accuracy, including near perfect edges and monolayers.

The Energy Department's Oak Ridge National Laboratory is creating a set of tools for fabricating perfect graphene sheets, including the recent finding that electron radiation prevents connections between monolayers.

Oak Ridge researchers used supercomputers to simulate the fabrication of graphene using quantum molecular dynamics. In the process, scientists claim to have uncovered a new method of fabricating perfect edges and monolayers in graphene.

Researchers reported last year on a method called Joule heating, that uses an electric current to trim graphene edges to perfection, albeit at the expense of creating structural loops that make connections between monolayers. Using quantum molecular dynamics in their supercomputer simulations, an intermediate step in the edge-formation process was discovered. The researchers harnessed that step to perfect the fabrication method.

The group now reports that using electron irradiation during the edge formation process prevents loops between layers from forming.