Preparation Of Modified Graphene And Its Terahertz Response

Great focus on graphene, an novel two-dimensional honeycomb nano-material, can be attributed to its remarkable mechanical, electrical, optical and thermal properties. It has the excellent application prospects in photoelectric devices and energy storage. The optoelectronics in terahertz (THz) region mainly focus on the generation, detection, transmission and modulation mechanism of the THz wave, which is regarded as a’gap’ between the infrared and microwave region in the electromagnetic spectrum resulted from short of efficient functional devices. THz carrier dynamics demonstrates intraband transitions in graphene, which make graphene become a promising material for the THz functional devices. Nevertheless, the intrinsic zero-gap properties and the relatively weak THz response of pristine graphene limit its applications in the future THz devices. The modified graphene can realize the modulation of the band structure and the enhancement of the THz response. So far there are only few reports on the THz response of the modified graphene. This paper consists of two parts.In the first part, the N-doped graphene, in which pyrrolic N bonding configuration is the dominant doping type, is synthesized by us. Then, we utilize THz time-domain spectroscopy to evaluate its THz transmission under different doping concentration. The results suggest that its THz transmission is proportional to its doping concentration, which is connected with its electrical conductivity.In the second part, we demonstrate a graphene-metamaterial hybrid structure and THz-TDS is utilized to evaluate its THz response. The hybrid structure can dramatically enhance the THz response of both metamaterials and graphene. A coupling model as well as numerical calculation has been used to fully investigate the influence of this coupling. The results suggest that a higher conductivity for stronger coupling. Substrate also could bring some effects on this coupling.