TY  - JOUR
AU  - Wang, Zhou-jun
AU  - Wei, Mingming
AU  - Jin, Li
AU  - Ning, Yanxiao
AU  - Yu, Liang
AU  - Fu, Qiang
AU  - Bao, Xinhe
PY  - 2013
TI  - Simultaneous N-intercalation and N-doping of epitaxial graphene on 6H-SiC(0001) through thermal reactions with ammonia
JO  - Nano Research
SN  - 1998-0124
SP  - 399
EP  - 408
VL  - 6
IS  - 6
AB  - 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 NH3-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 ℃, 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 ℃. 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.
UR  - https://doi.org/10.1007/s12274-013-0317-7
DO  - 10.1007/s12274-013-0317-7