title: Broadband terahertz modulation in electrostatically-doped artificial trilayer graphene.
abstract: 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.
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California, CA 90089, USA. ioannis.chatzakis.ctr.gr@nrl.naval.mil ioannis.chatzakis@gmail.com scronin@usc.edu.
authors.forename: Ioannis
authors.identifier: http://orcid.org/0000-0002-3568-2174
authors.initials: I
authors.lastname: Chatzakis
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California, CA 90089, USA. ioannis.chatzakis.ctr.gr@nrl.naval.mil ioannis.chatzakis@gmail.com scronin@usc.edu.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Chemistry, University of Southern California, Los Angeles, California, CA 90089, USA.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Benderskii
authors.affiliation: Department of Electrical Engineering, University of Southern California, Los Angeles, California, CA 90089, USA. ioannis.chatzakis.ctr.gr@nrl.naval.mil ioannis.chatzakis@gmail.com scronin@usc.edu and Department of Chemistry, University of Southern California, Los Angeles, California, CA 90089, USA and Department of Physics, University of Southern California, Los Angeles, California, CA 90089, USA.
authors.forename: Stephen B
authors.identifier: http://orcid.org/0000-0001-9153-7687
authors.initials: SB
authors.lastname: Cronin