Growth of non-concentric graphene ring on 6H-SiC surface
The diameter of graphene ring is small (about 500 nm). It is suitable to apply for nanodevice.
The fabrication method of the graphene ring is bottom up. Therefore the edge structure is intact.
The graphene ring is non-concentric and leads to the efficiency of optical antennas increase.
This method can control the size of graphene ring by adjusting annealing temperature and time.
Optical antennas are devices that efficiently convert the energy of free propagating radiation into localized energy and vice versa. Optical antennas can be applied for sensing, photodetection, light emission, spectroscopy and so on. In this report we have demonstrated the growth of off-center graphene rings by annealing Si-terminated 6H-SiC under inert gas pressure of 0.05 atm. The eccentricity of the graphene ring can increase the efficiency of optical antennas. In addition, this bottom-up fabrication method can keep ring edges intact unlike e-beam lithography. The edge structure of the ring is, moreover, armchair edge. We found that the width of the ring depends on annealing temperature and time.