Abstract-Broadband terahertz modulation in electrostatically-doped artificial trilayer graphene

Ioannis Chatzakis,*^a   Zhen Li,^a  Alexander V. Benderskii^b and   Stephen B. Cronin*^abc  

http://pubs.rsc.org/en/content/articlelanding/2017/nr/c6nr07054j#!divAbstract

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Corresponding authors

^a

Department of Electrical Engineering, University of 

Southern California, Los Angeles, California, USA
 E-mail: ioannis.chatzakis.ctr.gr@nrl.naval.mil,ioannis.chatzakis@gmail.com, scronin@usc.edu

^b

Department of Chemistry, University of Southern California, Los Angeles, California, USA

^c

Department of Physics, University of Southern California, Los Angeles, California, USA

We report a terahertz optical modulator consisting of randomly stacked trilayer graphene (TLG) deposited on an oxidized silicon substrate by means of THz-Time Domain Spectroscopy (THz-TDS). Here, the gate tuning of the Fermi level of the TLG provides the fundamental basis for the modulation of THz transmission. We measured a 15% change in the THz transmission of this device over a broad frequency range (0.6–1.6 THz). We also observed a strong absorption >80% in the time-domain signals and a frequency independence of the conductivity. Furthermore, unlike previous studies, we find that the underlying silicon substrate, which serves as a gate electrode for the graphene, also exhibits substantial modulation of the transmitted THz radiation under applied voltage biases.