Broadband terahertz modulation in electrostatically-doped artificial trilayer graphene

• Published in: Nanoscale Vol. 9; no. 4; pp. 1721 - 1726
• Main Authors: Chatzakis, Ioannis, Li, Zhen, Benderskii, Alexander V, Cronin, Stephen B
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 26.01.2017
• Subjects: Chemistry; Devices; Electrodes; Gates; Graphene; Materials Science; Modulation; Nanostructure; Physics; Science & Technology - Other Topics; Silicon substrates; Tuning
• ISSN: 2040-3364; 2040-3372; 2040-3372
• DOI: 10.1039/c6nr07054j

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. 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).