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Title: Effect of substrate material on the growth and field emission characteristics of large-area carbon nanotube forests

Carbon nanotubes (CNTs) are a promising replacement for tungsten filaments as electron emitters in conventional x-ray sources, owing to their higher aspect ratio, superior mechanical stability, chemical inertness, and high electrical and thermal conductivities. Conditions for realizing the best emission behavior from CNTs have been formulated over the last few years. In this paper, we report the relatively less-investigated factor, namely, the influence of the nature of substrate material on the growth as well as field emission characteristics of large-area multiwalled CNTs for their practical application in medical x-ray sources. We compare the morphology of CNTs on a variety of substrates such as stainless steel, copper, molybdenum, graphite, few-layer graphene, and carbon nanowalls grown by thermal chemical vapor deposition following a simple drop-coating of catalyst. We find that CNTs grown on stainless steel and graphite show the best combination of emission characteristics under pulsed operation mode. These studies are helpful in selecting the optimum substrate material for field emission applications. Ex situ studies on field emission degradation of CNTs are presented towards the end.
Authors:
; ; ;  [1] ; ;  [2] ;  [3] ;  [4]
  1. IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)
  2. Siemens Healthcare GmbH, Technology Centre, Guenther-Scharowsky-Strasse 1, 91058 Erlangen (Germany)
  3. Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstrasse 12, A-8700 Leoben (Austria)
  4. (Austria)
Publication Date:
OSTI Identifier:
22494942
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 119; Journal Issue: 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CARBON NANOTUBES; CHEMICAL VAPOR DEPOSITION; COPPER; FIELD EMISSION; FILAMENTS; GRAPHENE; GRAPHITE; LAYERS; MOLYBDENUM; MORPHOLOGY; OPERATION; PULSES; STABILITY; STAINLESS STEELS; SUBSTRATES; THERMAL CONDUCTIVITY; TUNGSTEN; X-RAY SOURCES