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Co 3 O 4 Nanostructures with Different Morphologies and their Field‐Emission Properties
Author(s) -
Varghese B.,
Teo C. H.,
Zhu Y.,
Reddy M. V.,
Chowdari B. V. R.,
Wee A. T. S.,
Tan V. B. C.,
Lim C. T.,
Sow C.H.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200700038
Subject(s) - materials science , nanowire , nanostructure , field electron emission , diffusion , nanotechnology , cobalt , chemical engineering , reactivity (psychology) , field (mathematics) , current density , oxygen , metallurgy , organic chemistry , medicine , chemistry , physics , alternative medicine , mathematics , pathology , quantum mechanics , pure mathematics , engineering , thermodynamics , electron
We report an efficient method to synthesize vertically aligned Co 3 O 4 nanostructures on the surface of cobalt foils. This synthesis is accomplished by simply heating the cobalt foils in the presence of oxygen gas. The resultant morphologies of the nanostructures can be tailored to be either one‐dimensional nanowires or two‐dimensional nanowalls by controlling the reactivity and the diffusion rate of the oxygen species during the growth process. A possible growth mechanism governing the formation of such nanostructures is discussed. The field‐emission properties of the as‐synthesized nanostructures are investigated in detail. The turn‐on field was determined to be 6.4 and 7.7 V μm –1 for nanowires and nanowalls, respectively. The nanowire samples show superior field‐emission characteristics with a lower turn‐on field and higher current density because of their sharp tip geometry and high aspect ratio.