Carrier dynamics in graphene: ultrafast many-particle phenomena

TL;DR

This paper reviews ultrafast carrier dynamics in graphene, highlighting phenomena like carrier multiplication and population inversion due to many-particle interactions, with implications for photodetectors and terahertz lasers.

Contribution

It provides a microscopic understanding of carrier relaxation processes and introduces new insights into ultrafast phenomena in graphene and Landau-quantized graphene.

Findings

Carrier multiplication significantly enhances charge carrier numbers.

Population inversion suggests potential for graphene-based terahertz lasers.

Ultrafast phonon and Coulomb interactions govern carrier relaxation.

Abstract

Graphene is an ideal material to study fundamental Coulomb- and phonon-induced carrier scattering processes. Its remarkable gapless and linear band structure opens up new carrier relaxation channels. In particular, Auger scattering bridging the valence and the conduction band changes the number of charge carriers and gives rise to a significant carrier multiplication - an ultrafast many-particle phenomenon that is promising for the design of highly efficient photodetectors. Furthermore, the vanishing density of states at the Dirac point combined with ultrafast phonon-induced intraband scattering results in an accumulation of carriers and a population inversion suggesting the design of graphene-based terahertz lasers. Here, we review our work on the ultrafast carrier dynamics in graphene and Landau-quantized graphene is presented providing a microscopic view on the appearance of carrier multiplication and population inversion.