Study Of Electromagnetic Characteristics Of 1D Grapheme Based On Modified FDTD Method

Graphene, a two-dimensional crystal structure composed of carbon atoms, is the thinnest material in the world at present.It has good electrical conductivity,zero band gap band structure and the unique light sensitive feature.Due to the unique optical properties of graphene, graphene has been widely concerned as a novel two-dimensional semiconductor material since it was got in 2004.There is big breakthrough in the research of the graphene in recent years and significant progress in the mass production of graphene.The artical is based on the finite difference time domain method(FDTD),combination with surface boundary condition method(SBC),we get the FDTD iterative of the normal incidence and oblique incidence of the Terahertz electromagnetic wave to single-layer graphene, calculate the reflection and transmission coefficients,and verify the correctness of the theory compared with the analytical solution.We apply the surface boundary condition to photonic crystals,study the absorption characteristics of the one dimensional graphene photonic crystal in the THZ wave range,change the position of graphene in the model,and get the relationship of the one dimensional graphene photonic crystal absorption characteristics and the position of graphene.It turns out,when the graphene is located on the surface of the photonic crystal, graphene and spacer layer constitute the surface defect on the surface of photonic crystal,which contributes the localization of light,the localization increases the ability that the graphene absorbs the terahertz electromagnetic wave energy.Then,we have time-domain finite difference calculation for certain thickness of graphene with the current density convolution method based on Laplace transform(LTJEC-FDTD),get the FDTD iterative of the vertical incident wave to the graphene in the Terahertz range,calculate the reflection and transmission coefficients,and verify the correctness of the theory compared with the analytical solution.We also use the modified FDTD algorithm of the oblique incidence to the one dimensional graphene photonic crystal, convert the two dimensional problem into one dimensional problem, have the incident wave through the transformation and modified connection boundary,solve the problem that the incident wave in the conventional way.Combining with the LTJEC-FDTD algorithm,we get the FDTD iterative of the oblique incident to the graphene of the electromagnetic in the Terahertz range,and verify the correctness of the theory compared the reflection and transmission coefficients with the analytical solution.At last,we study the electromagnetic properties of the graphene solar batteries’ transparent anode substrated by quartz glass by LTJEC-FDTD algorithm,comparing with the electromagnetic properties of the traditional indium tin oxide(ITO) solar batteries’ transparent anode.It turns out,in the low frequency, the electromagnetic properties of the graphene solar batteries is better.Taking the place of indium tin oxide(ITO) in the transparent electrode of organic solar cells,graphene has better performance and great development potential.