Ultrahigh speed graphene diode with reversible polarity

• Published in: Solid state communications Vol. 152; no. 19; pp. 1842 - 1845
• Main Authors: Moddel, Garret, Zhu, Zixu, Grover, Sachit, Joshi, Saumil
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.10.2012; Elsevier
• Subjects: A. Graphene; C. Diode; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Dirac point; D. Terahertz; Electron states and collective excitations in thin films, multilayers, quantum wells, mesoscopic and nanoscale systems; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Exact sciences and technology; Physics; Thin films and multilayers; D. Terahertz; A. Graphene; C. Diode; D. Dirac point; Rectification; Patterning; Mean free path; Etching; Diodes; Thin films; Graphene; Polarity; Transport processes; Carrier mobility; Carrier density
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2012.06.013

The ability to tune the carrier-type concentration ratio with applied field along with a mean-free path length approaching 1μm in graphene enables a new diode in which the diode polarity can be reversed. The diode consists of a thin graphene film with a geometric asymmetry that determines a preferred direction for charge-carrier transport, independent of whether the carriers are electrons or holes. We fabricated submicron geometric diodes by patterning and etching exfoliated graphene. Applying field-effect voltages to the substrate, we reversed the carrier type and demonstrated reversal of the diode polarity. The graphene geometric diodes exhibited rectification at 28THz, opening the way to ultrahigh speed applications for these versatile devices. ► Geometric diodes showing electrical asymmetry were formed from asymmetric graphene structures. ► The polarity of the electrical asymmetry is a function of carrier type. ► Carrier type and hence diode polarity reversed with shifting applied gate voltage. ► The graphene geometric diode operates at a frequency of at least 28THz. ► The reversible diodes can be applied to ultra-high-speed digital memory and flip–flops.