Summary: Carrier recombination and generation rates for intravalley and intervalley phonon scattering
in graphene
Farhan Rana,* Paul A. George, Jared H. Strait, Jahan Dawlaty, Shriram Shivaraman,
Mvs Chandrashekhar, and Michael G. Spencer
School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, USA
Received 5 January 2009; published 31 March 2009
Electron-hole generation and recombination rates for intravalley and intervalley phonon scattering in
graphene are presented. The transverse and the longitudinal optical phonon modes E2g modes near the zone
center point contribute to intravalley interband carrier scattering. At the zone edge K K point , only the
transverse optical phonon mode A1 mode contributes significantly to intervalley interband scattering with
recombination rates faster than those due to zone-center phonons. The calculated recombination times range
from less than a picosecond to more than hundreds of picoseconds and are strong functions of temperature and
electron and hole densities. The theoretical calculations agree well with experimental measurements of the
recombination rates of photoexcited carriers in graphene.
DOI: 10.1103/PhysRevB.79.115447 PACS number s : 73.63.Bd, 73.50.Gr, 72.10.Di, 73.61.Wp
I. INTRODUCTION
Graphene is a single two-dimensional atomic layer of car-
bon atoms forming a dense honeycomb crystal lattice.1­4 The
high mobility of electrons and holes in graphene has
prompted theoretical and experimental investigations into

Source: Afshari, Ehsan - School of Electrical and Computer Engineering, Cornell University

Collections: Engineering