Atom-by-atom spectroscopy at graphene edge
Atom-by-atom spectroscopy at graphene edge
复制标题
DOI：
10.1038/nature09664
复制
发表时间：
2010-12-23
期刊：
影响因子：
64.8
通讯作者：
Koshino, Masanori
中科院分区：
文献类型：
--
作者：
Suenaga, Kazu;Koshino, Masanori
许多纳米器件的特性对局部原子构型敏感，因此单个原子尺度上的元素识别和电子态分析变得越来越重要。例如，石墨烯被认为是未来器件的有希望的候选者，并且由这种材料构造的纳米器件的电子特性在很大程度上由边缘结构决定（1）。石墨烯边界的原子构型已通过透射电子显微镜和扫描隧道显微镜（2-4）进行了研究，但这些边缘态的电子性质尚未通过原子分辨率确定。虽然现在可以通过环形暗场成像（5）或电子能量损失光谱（6，7）实现单个原子水平的简单元素分析，但由于极弱的信号和电子束对样品的损伤，获得单个轻原子（如碳原子）的精细结构光谱信息受到阻碍。在这里，我们克服了这些困难，以证明在石墨烯边界的特定位点的单原子光谱，使直接调查的电子和键合结构的边缘原子，特别是，歧视单，双和三配位的碳原子实现原子分辨率。通过展示如何通过能量损失近边精细结构分析从单个原子中获得丰富的化学信息（8），我们的结果应该为探索各种纳米器件和单个分子的局部电子结构开辟道路。
The properties of many nanoscale devices are sensitive to local atomic configurations, and so elemental identification and electronic state analysis at the scale of individual atoms is becoming increasingly important. For example, graphene is regarded as a promising candidate for future devices, and the electronic properties of nanodevices constructed from this material are in large part governed by the edge structures(1). The atomic configurations at graphene boundaries have been investigated by transmission electron microscopy and scanning tunnelling microscopy(2-4), but the electronic properties of these edge states have not yet been determined with atomic resolution. Whereas simple elemental analysis at the level of single atoms can now be achieved by means of annular dark field imaging(5) or electron energy-loss spectroscopy(6,7), obtaining fine-structure spectroscopic information about individual light atoms such as those of carbon has been hampered by a combination of extremely weak signals and specimen damage by the electron beam. Here we overcome these difficulties to demonstrate site-specific single-atom spectroscopy at a graphene boundary, enabling direct investigation of the electronic and bonding structures of the edge atoms-in particular, discrimination of single-, double- and triple-coordinated carbon atoms is achieved with atomic resolution. By demonstrating how rich chemical information can be obtained from single atoms through energy-loss near-edge fine-structure analysis(8), our results should open the way to exploring the local electronic structures of various nanodevices and individual molecules.