Simultaneous N-intercalation and N-doping of epitaxial graphene on 6H-SiC（0001） through thermal reactions with ammonia

• Published in: 纳米研究：英文版 Vol. 6; no. 6; pp. 399 - 408
• Main Author: Zhou-jun Wang Mingming Wei Li Jin Yanxiao Ning Liang Yu Qiang Fu Xinhe Bao
• Format: Journal Article
• Language: English
• Published: 2013
• Subjects: 6H-SiC; X-射线光电子能谱; 低能电子衍射; 掺杂剂; 插层; 热反应; 石墨; 表面功能化
• ISSN: 1998-0124; 1998-0000

Surface functionalization of epitaxial graphene overlayers on 6H-SiC（0001） has been attempted through thermal reactions in NH3. X-ray photoelectron spectroscopy and micro-region low energy electron diffraction results show that a significant amount of N is present at the NHB-treated graphene surface, which results in strong band bending at the SiC surface as well as decoupling of the graphene overlayers from the substrate. The majority of the surface N species can be removed by annealing in vacuum up to 850 ~C, weakening the surface band bending and resuming the strong coupling of graphene with the SiC surface. The desorbed N atoms can be attributed to the intercalated species between graphene and SiC. Low temperature scanning tunneling spectroscopy and density functional theory simulations confirm the presence of N dopants in the graphene lattice, which are in the form of graphitic substitution and can be stable above 850 ~C. This is the first report of simultaneous N intercalation and N doping of epitaxial graphene overlayers on SiC, and it may be employed to alter the surface physical and chemical properties of epitaxial graphene overlayers.