Department of Materials Science and Engineering, Rutgers University, 607 Taylor Road, Piscataway, New Jersey 08854, United States.
ACS Nano. 2011 Jun 28;5(6):4945-52. doi: 10.1021/nn201043a. Epub 2011 May 27.
Point sources exhibit low threshold electron emission due to local field enhancement at the tip. The development and implementation of tip emitters have been hampered by the need to position them sufficiently apart to achieve field enhancement, limiting the number of emission sites and therefore the overall current. Here we report low threshold field (< 0.1 V/μm) emission of multiple electron beams from atomically thin edges of reduced graphene oxide (rGO). Field emission microscopy measurements show evidence for interference from emission sites that are separated by a few nanometers, suggesting that the emitted electron beams are coherent. On the basis of our high-resolution transmission electron microscopy, infrared spectroscopy, and simulation results, field emission from the rGO edge is attributed to a stable and unique aggregation of oxygen groups in the form of cyclic edge ethers. Such closely spaced electron beams from rGO offer prospects for novel applications and understanding the physics of linear electron sources.
由于尖端的局部场增强，点源表现出低阈值电子发射。由于需要将它们彼此足够隔开以实现场增强，尖端发射器的开发和实施受到阻碍，这限制了发射点的数量，从而限制了总的电流。在这里，我们报告了来自还原氧化石墨烯（rGO）原子薄边缘的多个电子束的低阈值场（<0.1 V/μm）发射。场发射显微镜测量显示了来自相隔几个纳米的发射点的干涉的证据，表明发射的电子束是相干的。基于我们的高分辨率透射电子显微镜、红外光谱和模拟结果，rGO 边缘的场发射归因于以环状边缘醚的形式稳定且独特的氧基团聚集。rGO 中的这种紧密间隔的电子束为新型应用和理解线性电子源的物理特性提供了前景。
