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This content will become publicly available on November 19, 2017

Title: Integrating carbon nanotube forests into polysilicon MEMS: Growth kinetics, mechanisms, and adhesion

The growth of carbon nanotubes (CNTs) on polycrystalline silicon substrates was studied to improve the design of CNT field emission sources for microelectromechanical systems (MEMS) applications and vacuum microelectronic devices (VMDs). Microwave plasma-enhanced chemical vapor deposition (PECVD) was used for CNT growth, resulting in CNTs that incorporate the catalyst particle at their base. The kinetics of CNT growth on polysilicon were compared to growth on Si (100) using the model of Deal and Grove, finding activation energies of 1.61 and 1.54 eV for the nucleation phase of growth and 1.90 and 3.69 eV for the diffusion-limited phase on Si (100) and polysilicon, respectively. Diffusivity values for growth on polysilicon were notably lower than the corresponding values on Si (100) and the growth process became diffusion-limited earlier. Evidence favors a surface diffusion growth mechanism involving diffusion of carbon precursor species along the length of the CNT forest to the catalyst at the base. Explanations for the differences in activation energies and diffusivities were elucidated by SEM analysis of the catalyst nanoparticle arrays and through wide-angle X-ray scattering (WAXS) of CNT forests. As a result, methods are presented to improve adhesion of CNT films during operation as field emitters, resulting in amore » 2.5× improvement.« less
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [1] ;  [1]
  1. Duke Univ., Durham, NC (United States)
  2. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  3. Research Triangle Institute (RTI) International, Durham, NC (United States)
Publication Date:
OSTI Identifier:
1332934
Grant/Contract Number:
AR0000546
Type:
Accepted Manuscript
Journal Name:
Carbon
Additional Journal Information:
Journal Name: Carbon; Journal ID: ISSN 0008-6223
Publisher:
Elsevier
Research Org:
Duke Univ., Durham, NC (United States)
Sponsoring Org:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; 36 MATERIALS SCIENCE