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Inorganic Nanowires as Future Active Components in Opto-Electronics
One-dimensional semiconducting and metallic nanowires are considered as one key element for
the next generation of electronic, optical, and magnetic devices. Copper and copper-based
nanostructures are one of the most interesting materials for microelectronics. Studies on
Cu(OH)2, as a possible starting point to design copper nanostructures, yielded to the
successful synthesis of nanoribbons of Cu(OH)2 with a diameter of 10-15 nm and a
length up to 3µm. Their magnetic properties (S=1/2) originate from antiferromagnetic
interactions between Cu2+ spins bridged by OH groups.
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Figure 1: (left) TEM image of Cu(OH)2 nanoribbons synthesized with addition of
ammonia. These nanoribbons tend to form bundles and can reach a length up to 3µm.
(right) The temperature dependence of the magnetic susceptibility of as-prepared
(solid circles) and aged (open circles) Cu(OH)2 samples.
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Semiconducting ZnO is also a very interesting material for its potential applications in
numerous fields: as a direct wide band gap (3.37 eV) semiconductor with a large exciton
energy (60 meV), it exhibits near-UV emission, transparent conductivity, piezoelectricity,
and excellent mechanical properties (Young modulus ~ 120 GPa, hardness ~ 10 GPa). The
synthesis of one-dimensional single-crystalline ZnO nanostructures has been of growing
interest owing to their promising application in nanoscale optoelectronic devices.
Semiconducting ZnO nanowires were produced in a CVD fixed-bed furnace by vaporizing Zn
powders over a thin Au film deposited on (001) Si substrate. The Zn vapour reacted with
the Au catalyst to form alloy droplets, and ZnO nanowires were formed by
vapour-liquid-solid reaction. SEM and TEM observations revealed that the ZnO nanowires
are singlecrystalline and have diameters ranging from 10 up to 100 nm and a length up to
2µm. For the second phase of the NCCR Nanoscience the production of ordered arrays of ZnO
nanowires and exploration of their application in electronic and optical devices as well
as for chemical detection is foreseen.
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Figure 2: (left) SEM image of ZnO nanowires catalysed by Au
particles. (middle) High-resolution TEM image shows a single crystalline ZnO with
a diameter of about 25 nm. (right) Energy-dispersive analysis confirms the composition of ZnO.
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Reference:
P. Umek, J.W. Seo, L. Forró, P. Cevc, Z. Jaglicic, M. Skarabot, A. Zorko, and D. Arcon
“Synthesis and Magnetic Characterisation of Cu(OH)2 nanoribbons”, in preparation.
Contact:
László Forró |
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EPF Lausanne
Switzerland
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