title: Ultrafast transient absorption microscopy studies of carrier dynamics in epitaxial graphene.
abstract: Transient absorption microscopy was employed to image charge carrier dynamics in epitaxial multilayer graphene. The carrier cooling exhibited a biexponential decay that showed a significant dependence on carrier density. The fast and slow relaxation times were assigned to coupling between electrons and optical phonon modes and the hot phonon effect, respectively. The limiting value of the slow relaxation time at high pump intensity reflects the lifetime of the optical phonons. Significant spatial heterogeneity in the dynamics was observed due to differences in coupling between graphene layers and the substrate.
authors.affiliation: Notre Dame Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA. lhuang2@nd.edu
authors.forename: Libai
authors.initials: L
authors.lastname: Huang
authors.forename: Gregory V
authors.initials: GV
authors.lastname: Hartland
authors.forename: Li-Qiang
authors.initials: LQ
authors.lastname: Chu
authors.lastname: Luxmi
authors.forename: Randall M
authors.initials: RM
authors.lastname: Feenstra
authors.forename: Chuanxin
authors.initials: C
authors.lastname: Lian
authors.forename: Kristof
authors.initials: K
authors.lastname: Tahy
authors.forename: Huili
authors.initials: H
authors.lastname: Xing
mesh_terms: D006108:Graphite / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation / Q000379:methods*; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics
chemical_list: D006108:Graphite