Xiaodong Feng, Min Hu *, Jun Zhou, and Shenggang Liu
University of Electronic Science and Technology of China
Terahertz Science and Technology Research Center, Chengdu, China
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Abstract: We present a combination for centimetre scale quantitative graphene conductivity mapping by terahertz time-domain transmission and reflection spectroscopy in the frequency range 0.5 THz to 2.5 THz. The results agree well with each other and show that a higher signal-to-noise ratio is acquired through reflection measurement as a result of less influence of pollutants on the back of the substrate. Therefore, we can use terahertz reflection spectroscopy for graphene conductivity on any non-metallic substrates including substrates that THz wave cannot get through well. The graphene conductivity is well fitted by the Drude-Smith formula, which indicates the remarkable impact of carrier backscattering. Furthermore, we employ THz time-domain reflection spectroscopy for graphene conductivity mapping of a graphene/Si sample and find regional differences of the conductivity which can contribute to graphene surface plasmon polaritons and graphene modulators.
Keywords: Graphene conductivity, Terahertz spectroscopy, Transmission, Reflection, Drude-smith
Acknowledgment: This work is supported by National Key Program of Fundamental Research of China under Contract No. 2014CB339801, National Natural Science Foundation of China under Contract No. 61231005 and Contract No. 11305030.
Cite this article:
Xiaodong Feng, Min Hu, Jun Zhou, and Shenggang Liu. Graphene conductivity mapping by terahertz time-domain reflection spectroscopy[J]. International Journal of Terahertz Science and Technology, 2016, Vol.9, No.3: 109-116. DOI:10.11906/TST.109-116.2016.09.11