Stability and spectroscopy of single nitrogen dopants in graphene at elevated temperatures.
Stability and spectroscopy of single nitrogen dopants in graphene at elevated temperatures.
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DOI：
10.1021/nn5054798
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发表时间：
2014-11
期刊：
影响因子：
17.1
通讯作者：
J. Warner;Yung‐Chang Lin;Kuang He;M. Koshino;K. Suenaga
中科院分区：
文献类型：
--
作者：
J. Warner;Yung‐Chang Lin;Kuang He;M. Koshino;K. Suenaga
利用原子分辨率扫描透射电子显微镜（STEM）结合电子能量损失谱（EELS）研究了石墨烯中的单氮（N）掺杂。使用500 °C的原位加热保持器为我们提供了干净的石墨烯表面，并且我们证明了即使在局部sp（2）键重构期间，孤立的N取代原子在石墨烯晶格中保持局部化和稳定。隔离的N掺杂剂的高稳定性使我们能够同时获得2D EELS图和ADF-STEM图像，以绘制出局部键合变化。我们表明，取代N掺杂剂的碳（C）原子的EELS的变化，它是直接键合。C K边EELS的π* 峰的上移为10.5 eV，并得到密度泛函理论模拟的支持。
Single nitrogen (N) dopants in graphene are investigated using atomic-resolution scanning transmission electron microscopy (STEM) combined with electron energy loss spectroscopy (EELS). Using an in situ heating holder at 500 °C provided us with clean graphene surfaces, and we demonstrate that isolated N substitutional atoms remain localized and stable in the graphene lattice even during local sp(2) bond reconstruction. The high stability of isolated N dopants enabled us to acquire 2D EELS maps with simultaneous ADF-STEM images to map out the local bonding variations. We show that a substitutional N dopant causes changes in the EELS of the carbon (C) atoms it is directly bonded to. An upshift in the π* peak of the C K-edge EELS of ∼0.5 eV is resolved and supported by density functional theory simulations.