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Effects of Interlayer Coupling on Hot‐Carrier Dynamics in Graphene‐Derived van der Waals Heterostructures
Author(s) -
Narang Prineha,
Zhao Litao,
Claybrook Steven,
Sundararaman Ravishankar
Publication year - 2017
Publication title -
advanced optical materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.89
H-Index - 91
ISSN - 2195-1071
DOI - 10.1002/adom.201600914
Subject(s) - graphene , materials science , heterojunction , graphite , condensed matter physics , dielectric , plasmon , phonon , ab initio , scattering , chemical physics , optoelectronics , nanotechnology , optics , physics , quantum mechanics , composite material
Graphene exhibits promise as a plasmonic material with high mode confinement that could enable efficient hot carrier extraction. The lifetimes and mean free paths of energetic carriers have been investigated in free‐standing graphene, graphite, and a heterostructure consisting of alternating graphene and hexagonal boron nitride layers using ab initio calculations of electron–electron and electron–phonon scattering in these materials. It is found that the extremely high lifetimes (3 ps) of low‐energy carriers near the Dirac point in graphene, which are a 100 times larger than that in noble metals, are reduced by an order of magnitude due to interlayer coupling in graphite, but enhanced in the heterostructure due to phonon mode clamping. However, these lifetimes drop precipitously with increasing carrier energy and are smaller than those in noble metals at energies exceeding 0.5 eV. By analyzing the contribution of different scattering mechanisms and interlayer interactions, desirable spacer layer characteristics—high dielectric constant and heavy atoms—that could pave the way for plasmonic heterostructures with improved hot carrier transport have been identified.