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Title: Introducing thermally stable inter-tube defects to assist off-axial phonon transport in carbon nanotube films

Through integrated molecular dynamics (MD) simulations and experimental studies, we demonstrated the feasibility of an ion-irradiation-and-annealing based phonon engineering technique to enhance thermal conductivity of carbon nanotube (CNT) films. Upon ion irradiation of CNT films, both inter-tube defects and intra-tube defects are introduced. Our MD simulations show that inter-tube defects created between neighboring tubes are much more stable than intra-tube defects created on tube graphitic planes. Upon thermal annealing, intra-tube defects are preferentially removed but inter-tube defects stay. Consequently, axial phonon transport increases due to reduced phonon scattering and off-axial phonon transport is sustained due to the high stability of inter-tube defects, leading to a conductivity enhancement upon annealing. The modeling predictions agree with experimental observations that thermal conductivities of CNT films were enhanced after 2 MeV hydrogen ion irradiations and conductivities were further enhanced upon post irradiation annealing.
Authors:
 [1] ; ; ; ;  [2] ;  [1] ;  [3]
  1. Department of Materials Science and Engineering, Texas A and M University, College Station, Texas 77843 (United States)
  2. Department of Nuclear Engineering, Texas A and M University, College Station, Texas, 77843 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22273414
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ANNEALING; CARBON NANOTUBES; CRYSTAL DEFECTS; GRAPHITE; MOLECULAR DYNAMICS METHOD; PHONONS; THERMAL CONDUCTIVITY; THIN FILMS