Mechanism and modulation of terahertz generation from a semimetal - graphite

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Semi-metals might offer a stronger interaction and a better confinement for terahertz wave than semiconductors, while preserve tunability. Particularly, graphene-based materials are envisioned as terahertz modulators, filters and ultra-broadband sources. However, the understanding of terahertz generation from those materials is still not clear, thus limits us recognizing the potential and improving device performances. Graphite, the mother material of graphene and a typical bulk semi-metal, is a good system to study semi-metals and graphene-based materials. Here we experimentally modulate and maximize the terahertz signal from graphite surface, thus reveal the mechanism - surface field driving photon induced carriers into transient current to radiate terahertz wave. We also discuss the differences between graphite and semiconductors; particularly graphite shows very weak temperature dependency from room temperature to 80 °C. Above knowledge will help us understand terahertz generations, achieve maximum output and electric modulation, in semi-metal or graphene based devices.

Related collections

Most cited references 39

Record: found
Abstract: not found
Article: not found

Efficient iterative schemes forab initiototal-energy calculations using a plane-wave basis set

G Kresse, J. Furthmüller (1996)

0 comments Cited 18090 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: not found
Article: not found

Generalized Gradient Approximation Made Simple.

Gary H. Perdew, Ernzerhof, M Perdew … (1997)

0 comments Cited 2071 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Graphene plasmonics for tunable terahertz metamaterials.

Long Ju, Baisong Geng, Jason Horng … (2011)

Plasmons describe collective oscillations of electrons. They have a fundamental role in the dynamic responses of electron systems and form the basis of research into optical metamaterials. Plasmons of two-dimensional massless electrons, as present in graphene, show unusual behaviour that enables new tunable plasmonic metamaterials and, potentially, optoelectronic applications in the terahertz frequency range. Here we explore plasmon excitations in engineered graphene micro-ribbon arrays. We demonstrate that graphene plasmon resonances can be tuned over a broad terahertz frequency range by changing micro-ribbon width and in situ electrostatic doping. The ribbon width and carrier doping dependences of graphene plasmon frequency demonstrate power-law behaviour characteristic of two-dimensional massless Dirac electrons. The plasmon resonances have remarkably large oscillator strengths, resulting in prominent room-temperature optical absorption peaks. In comparison, plasmon absorption in a conventional two-dimensional electron gas was observed only at 4.2 K (refs 13, 14). The results represent a first look at light-plasmon coupling in graphene and point to potential graphene-based terahertz metamaterials.