CNT-Graphene Junction Phonon Transmission

posted Jun 14, 2013, 8:37 AM by Timothy Fisher   [ updated Jun 16, 2013, 5:52 AM by Tim Fisher ]

Student: Jingjing Shi

Faculty: Tim Fisher, Xiulin Ruan

Sponsor: Air Force Office of Scientific Research

Summary: Carbon nanotubes and graphene offer high thermal conductivity, in addition to exceptional functions as electronic devices and sensors. However, both materials exhibit significant anisotropy in their thermal conduction that limits their three-dimensional thermal transport performance. Pillared-graphene structures that produce a three-dimensional network combining the grapheme sheets and carbon-nanotubes can address this deficiency. Hierarchical nanostructures inevitably suffer from the interfaces and junctions, however. This work predicts phonon heat transfer within the CNT-graphene junctions from theoretical calculations. The most commonly applied theoretical models for predicting transmission coefficients are the acoustic mismatch model (AMM) and the diffuse mismatch model (DMM). Both models are used in this work for the zigzag and armchair directions of graphene. In order to calculate the transmission coefficient, phonon group velocity is obtained from the slope of the phonon dispersion relation in CNTs and both zigzag and armchair graphene. Eventually, more advanced models such as the atomistic Green’s function method will be applied.

Representative Paper: