Zhao Wei, Xia Bingyu, Lin Li, Xiao Xiaoyang, Liu Peng, Lin Xiaoyang, Peng Hailin, Zhu Yuanmin, Yu Rong, Lei Peng, Wang Jiangtao, Zhang Lina, Xu Yong, Zhao Mingwen, Peng Lianmao, Li Qunqing, Duan Wenhui, Liu Zhongfan, Fan Shoushan, Jiang Kaili
State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics and Tsinghua-Foxconn Nanotechnology Research Center, Tsinghua University, Beijing 100084, China.
Center for Nanochemistry, Beijing Science and Engineering Center for Nanocarbons, Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Sci Adv. 2017 Sep 1;3(9):e1603231. doi: 10.1126/sciadv.1603231. eCollection 2017 Sep.
Two-dimensional (2D) materials have attracted interest because of their excellent properties and potential applications. A key step in realizing industrial applications is to synthesize wafer-scale single-crystal samples. Until now, single-crystal samples, such as graphene domains up to the centimeter scale, have been synthesized. However, a new challenge is to efficiently characterize large-area samples. Currently, the crystalline characterization of these samples still relies on selected-area electron diffraction (SAED) or low-energy electron diffraction (LEED), which is more suitable for characterizing very small local regions. This paper presents a highly efficient characterization technique that adopts a low-energy electrostatically focused electron gun and a super-aligned carbon nanotube (SACNT) film sample support. It allows rapid crystalline characterization of large-area graphene through a single photograph of a transmission-diffracted image at a large beam size. Additionally, the low-energy electron beam enables the observation of a unique diffraction pattern of adsorbates on the suspended graphene at room temperature. This work presents a simple and convenient method for characterizing the macroscopic structures of 2D materials, and the instrument we constructed allows the study of the weak interaction with 2D materials.
二维（2D）材料因其优异的性能和潜在的应用而备受关注。实现工业应用的关键一步是合成晶圆级单晶样品。到目前为止，已经合成了单晶样品，例如厘米级的石墨烯畴。然而，一个新的挑战是有效地表征大面积样品。目前，这些样品的晶体表征仍然依赖于选区电子衍射（SAED）或低能电子衍射（LEED），这更适合于表征非常小的局部区域。本文提出了一种高效的表征技术，该技术采用低能静电聚焦电子枪和超对齐碳纳米管（SACNT）薄膜样品支架。它允许通过在大束斑尺寸下拍摄一张透射衍射图像来快速对大面积石墨烯进行晶体表征。此外，低能电子束能够在室温下观察悬浮石墨烯上吸附物的独特衍射图案。这项工作提出了一种简单方便的方法来表征二维材料的宏观结构，并且我们构建的仪器允许研究与二维材料的弱相互作用。
