SUMMARY

Thermal transport at the interfaces of low-dimensional carbon nano-structures such as carbon nanotube (CNT) and graphene interfaces become very important in their nano-electronic devices. A fundamental understanding of phonon transport at these interfaces is required for the energy efficient design of CNTs and graphene devices. This work is aimed to investigate the phonon interactions and heat dissipation at interfaces of CNTs, to predict the phonon transmission and thermal boundary conductance (TBC) at graphene/metal interfaces, and to analyze the effect of electron-phonon coupling at graphene/metal interfaces on TBC. The present proposal consists of three parts all of which focus on the typical interfaces of CNTs or graphene in their electronic devices. The first part deals with the various interfaces of CNTs such as interfaces between layers of double-wall CNTs (DWNTs), CNT-CNT junctions and CNT-substrate interfaces. The coupling of vibration modes and energy exchange between layers of DWNTs is investigated using molecular dynamics (MD) simulations in the framework of travelling wave packets. Heat dissipation at CNT junctions supported on the silicon dioxide substrate is then investigated using MD simulations and methods for phonon spectrum analysis. The second part of the proposal aims at analyzing the effects of graphene-metal interactions on the thermal transport in single layer graphene (SLG). The contributions of different phonon modes to the thermal conductivity of isolated and Cu supported single layer graphene (SLG) are investigated using equilibrium MD simulations and relaxation time approximation method. The third part focuses on the nature of bonding, charge transfer, and electron-phonon interactions at graphene-metal interfaces which can be better described using density functional theory (DFT) calculations and atomistic Green’s Function (AGF) method. The phonon and electron transmission and their contribution to TBC across graphene/Cu interface are studied using AGF method and Landauer formalism. The electron-phonon coupling at SLG/metal interfaces will be considered in the AGF calculations and its effects on TBC will be explored. Our investigations of the interfacial thermal transport will provide insights to engineer the thermal properties of CNTs and graphene interfaces to improve the performance of their electronic devices.