Dr.Lim's Paper(Nano Letters) highlighted in NANO INFO. NO. 20
[한국] 그래핀 전계효과트랜지스터의 비선형 전도도 연구
http://www.nnpc.re.kr/nnpc/wsp/trend/trendView.jsp?status=technology&tr_seqno=12903&menu=0302
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Title: Gate-Controlled Nonlinear Conductivity of Dirac Fermion in Graphene Field-Effect Transistors Measured by Terahertz Time-Domain
Autor : Inhee Maeng, Seongchu Lim, Seung Jin Chae, Young Hee Lee, Hyunyong Choi, and Joo-Hiuk Son
Abstract : We present terahertz spectroscopic measurements of Dirac fermion dynamics from a large-scale graphene that was grown by chemical vapor deposition and on which carrier density was modulated by electrostatic and chemical doping. The measured frequency-dependent optical sheet conductivity of graphene shows electron-density-dependence characteristics, which can be understood by a simple Drude model. In a low carrier density regime, the optical sheet conductivity of graphene is constant regardless of the applied gate voltage, but in a high carrier density regime, it has nonlinear behavior with respect to the applied gate voltage. Chemical doping using viologen was found to be efficient in controlling the equilibrium Fermi level without sacrificing the unique carrier dynamics of graphene.