Effect of hydrogenation on graphene thermal transport

BARBARINO, GIULIANA;MELIS, CLAUDIO;COLOMBO, LUCIANO

2014-01-01

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Abstract

We studied thermal conductivity of the three most stable hydrogenated graphene (graphane) conformers by means of non equilibrium molecular dynamics. We estimated thermal conductivity for pristine graphene with sample length 2.1 (2.4) mu m as large as kappa = 745.4+/- 0.3 and 819.1 +/- 0.3 W m(-1)K(-1) in the armchair and zigzag directions, respectively, in very good agreement with previous theoretical results based on the Boltzmann transport equation. In the case of the three graphane isomers we observed a dramatic kappa reduction by at least one order of magnitude with respect to pristine graphene. We elucidated this reduction in terms of different phonon density of states and mean-free path distribution between graphene and graphane. The deterioration of thermal transport upon hydrogenation in graphene, could be proposed as a way to tune thermal transport in graphene for phononic applications such as thermal diodes.