Interfaces play a crucial role in electrical and thermal transport related structure-property relationships in many different areas of scientific interests, including composites and electronics reliability. Within the specialized field of nanoelectronics, fabrication of carbon nanotube (CNT) based devices has attained consistent attention, partly due to their excellent electrical and thermal transport properties. However, the use of CNT devices has still been limited because of their unknown performance reliability and variability. Often, CNT junction interfaces act as limiting factor in achieving optimal transport properties. In this context, we will describe non-equilibrium molecular dynamics simulations to characterize the cross-contact thermal transport for CNTs and graphene nanoribbons (GNRs). We find that length, diameter, number of walls (in MWCNTs), and degree of CNT deformation, all play important roles towards determination of contact conductance. For GNRs, the aspect ratio of the nanoribbons best characterizes the lateral thermal conductance. The observations will be discussed using several vibrational features associated with out of plane phonon modes observed in thermally anisotropic materials, such as CNTs and GNRs. We will also briefly discuss the electronic transmission features of metallic nanotubes as calculated using non-equilibrium Green’s function method within the framework of tight binding density functional theory for different inter-CNT lateral distances. Using estimated contact conductance, a multi-scale approach, based on statistical distribution of effective contact resistances (based on CNT distance) that originates from thermal fluctuations of intermolecular distances, is employed to predict effective electrical conductivity in polymeric matrix materials as a function of temperature.

Molecular modeling of electrical and thermal resistance across carbon nanotube and graphene nanoribbon contacts

249th National Meeting (2015)

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