▎ 摘　　要

The influence of different substrates on the photocarrier relaxation dynamics in monolayer graphene during the early stages of thermalization and cooling is explored and analyzed by means of ensemble Monte Carlo simulations. In addition, phonon dynamics of both intrinsic and surface polar modes associated to the interface between graphene and the underlying substrate are investigated. Suspended graphene and graphene on four of the most common substrates used for nanoelectronics will be studied, showing that depending on the case, carrier relaxation can be accelerated due to the leading role that the surface polar phonon modes take under such out-of-equilibrium situations. Among the considered cases, graphene onAl(2)O(3)shows the highest relaxation rates, while the results of graphene on h-BN, SiO2 and SiC are quitesimilar. On its behalf, photocarriers in suspended graphene take longer to thermalize than any of the substrate supported cases. (C) 2017 Elsevier B.V. All rights reserved.