Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan.
ACS Nano. 2013 Aug 27;7(8):6522-32. doi: 10.1021/nn402102y. Epub 2013 Jul 30.
A significant advance toward achieving practical applications of graphene as a two-dimensional material in nanoelectronics would be provided by successful synthesis of both n-type and p-type doped graphene. However, reliable doping and a thorough understanding of carrier transport in the presence of charged impurities governed by ionized donors or acceptors in the graphene lattice are still lacking. Here we report experimental realization of few-layer nitrogen-doped (N-doped) graphene sheets by chemical vapor deposition of organic molecule 1,3,5-triazine on Cu metal catalyst. When reducing the growth temperature, the atomic percentage of nitrogen doping is raised from 2.1% to 5.6%. With increasing doping concentration, N-doped graphene sheet exhibits a crossover from p-type to n-type behavior accompanied by a strong enhancement of electron-hole transport asymmetry, manifesting the influence of incorporated nitrogen impurities. In addition, by analyzing the data of X-ray photoelectron spectroscopy, Raman spectroscopy, and electrical measurements, we show that pyridinic and pyrrolic N impurities play an important role in determining the transport behavior of carriers in our N-doped graphene sheets.
实现将石墨烯作为二维材料应用于纳米电子学的重要进展将来自成功合成 n 型和 p 型掺杂石墨烯。然而，在存在由石墨烯晶格中离化施主或受主控制的带电杂质的情况下，可靠掺杂和对载流子输运的深入理解仍然缺乏。在这里，我们通过在 Cu 金属催化剂上化学气相沉积有机分子 1,3,5-三嗪，报告了少层氮掺杂（N 掺杂）石墨烯片的实验实现。当降低生长温度时，氮掺杂的原子百分比从 2.1%提高到 5.6%。随着掺杂浓度的增加，N 掺杂石墨烯片表现出从 p 型到 n 型的转变，同时电子-空穴输运的不对称性也得到了强烈增强，这表明了掺入的氮杂质的影响。此外，通过分析 X 射线光电子能谱、拉曼光谱和电测量的数据，我们表明吡啶和吡咯 N 杂质在确定我们的 N 掺杂石墨烯片中载流子的输运行为方面起着重要作用。
