Research Of Modulation Effect In Terahertz Rigon Based On Graphene

Terahertz technology has important applications in sensing and high-speed wirelesscommunications. However, devices related to beam control in terahertz range are very scarce,which severely restricted the applications o f terahertz technology. Graphene which presentsthe unique properties of strong mechanical strength, very-high electronic and thermalconductivity and high air-tightness attracts a lot of attentions recently. Due to its outstandingfeatures, Graphene have an extremely wide range of application. The applications ofgraphene are researched a lot recently, including research on graphene-metal heterostructuresand terahertz modulator. The natural correlation between Graphene and terahertz wavesmakes it necessary to research on the modulation effect in the graphene in terahertz band.Based on the relaxation time approximation of the Boltzmann equation, the impact ofgraphene on electronic transmission collision was analyzed, including elastic scattering andinelastic scattering in this thesis. Then the influences of the acoustic phonon, optical phonon,line edge roughness and impurities on the transport of electrons in grapheme are compared.The results show that impurity scattering, acoustic phonon scattering, and line edgeroughness scattering are the greatest impact factors on electronic transport in graphene.At last, on the basis of the discussion of the scattering and the electronic band structureof grapheme, electron mobility in graphene nano-band under different external conditions(such as temperature, the external voltage, the electron line density, impurity scattering rateand line edge roughness) was calculated. The change of graphene conductivity was obtainedthereafter. The transmittance of the terahertz in grapheme nano-band could be calculatedthrough the relationship between the transmittance and electrical conductivity at last. Theresults indicate the terahertz modulation depth of graphene is2.6%.