Strain analysis of noble metal islands grown on multiwalled carbon nanotubes

We analyze the local microscopic deformation left by Au, Ag and Cu islands on carbon nanotube walls observed by transmission electron microscopy. We employ finite-element simulations within continuum elasticity theory to demonstrate that the observed deformation of the tube walls is the result of elastic strain energy relaxation induced by the nucleation of noble metal clusters on the graphene lattice. We find that the magnitude of the tube deformation is strictly correlated to the lattice mismatch of the metal/carbon system under study. In this context, the tube deformation under the island is a proof of the pseudomorphical character of the system, even in the case of high lattice misfit (∼15%) as for Au and Ag.