Ultrafast Carrier Recombination and Generation Rates for Plasmon Emission and Absorption in Graphene

TL;DR

This paper investigates ultrafast electron-hole recombination and generation rates in graphene, highlighting their dependence on energy, density, temperature, and substrate effects, with implications for plasmon-based optoelectronic applications.

Contribution

It provides detailed measurements and analysis of carrier recombination and generation times in graphene, including effects of substrate hybridization with surface phonons.

Findings

Recombination times range from tens of femtoseconds to hundreds of picoseconds.

Carrier lifetimes are longer near the Dirac point compared to higher energies.

Plasmon dispersion is modified by hybridization with surface optical phonons.

Abstract

Electron-hole generation and recombination rates for plasmon emission and absorption in Graphene are presented. The recombination times of carriers due to plasmon emission have been found to be in the tens of femtoseconds to hundreds of picoseconds range. The recombination times depend sensitively on the carrier energy, carrier density, temperature, and the plasmon dispersion. Carriers near the Dirac point are found to have much longer lifetimes compared to carriers at higher energies. Plasmons in a Graphene layer on a polar substrate hybridize with the surface optical phonons and this hybridization modifies the plasmon dispersion. We also present generation and recombination rates of carriers due to plasmon emission and absorption in Graphene layers on polar substrates.