580
H. Yu. Mykhailova et al.
nanotube but also the entire array of nanostructures. Considerable attention to radiation defects has arisen in clarifying the possibility of using nanotubes in space and
nuclear reactors.
Electrophysical properties of isolated CNT are investigated in many laboratories
of the world for their application in nanoelectronics. The properties of an individual
nanotube are known to some extent—along the axis, it is a good conductor of current
and heat, but in the radial direction, the motion of charge carriers and phonons is
limited to an outer cylindrical carbon layer. To expand the scope of CNT, it is necessary to increase the flow of heat and current, for which it is necessary to investigate
their properties in the bulk or consolidated state. In a bulk state, the CNT, as a rule,
does not conduct an electric current, but with a slight compression, the situation is
changing.
The properties of an array of carbon nanotubes or a material containing CNT
differ from the properties of individual nanotubes (single-layered or multilayered).
An array of CNTs, unlike individual nanotubes, may not conduct an electric current.
This is due to the fact that the connections between adjacent nanotubes are van der
Waals.
Adding a small amount of CNT to a dielectric matrix facilitates the appearance
of electrical conductivity [1–6], whose size has a wide range. This dispersion in
the magnitude of electrical conductivity is reflected by the complex interaction of
various factors, the most important of which are the own conductivity of CNTs and
their contact resistance.
The electrical conductivity of the individual BWNT is 10
4 –10
7 (m)
−1 [7–9], the
measured contact resistance for the SCNT bundle is 100–400 k for metal/metal or
semiconductor/semiconductor compounds and twice that for metal/semiconductor
systems [10].
Defects in CNT may occur during synthesis (growth defects) or during external
influences, for example, high-energy irradiation.
Experimentally obtained nanostructures may contain defects that lead to the
distortion of their structure and differences in properties. The formation of curved,
colloid, swirling CNTs, as well as tubes of variable diameters occur only in the presence of topological defects associated with re-hybridization and unsaturated bonds
[11].
Topological defects can disappear when heated to a temperature of up to 2773 K
and higher in an inert medium.
In nanostructured materials, the peculiarity of the atomic structure is that each
element of the system or nanocomposite has a local structure of the free volume,
which leads to the appearance of potential barriers limiting the charge carriers in
the 1-to-2D (interlayer intervals of MCNT) on the boundary, 2-to-1D (in CNT) or
3-to-0D (fullerenes in the matrix and isolated clusters) directions, and the electronic
processes are predominantly quantum in nature.
H. Yu. Mykhailova et al.
nanotube but also the entire array of nanostructures. Considerable attention to radiation defects has arisen in clarifying the possibility of using nanotubes in space and
nuclear reactors.
Electrophysical properties of isolated CNT are investigated in many laboratories
of the world for their application in nanoelectronics. The properties of an individual
nanotube are known to some extent—along the axis, it is a good conductor of current
and heat, but in the radial direction, the motion of charge carriers and phonons is
limited to an outer cylindrical carbon layer. To expand the scope of CNT, it is necessary to increase the flow of heat and current, for which it is necessary to investigate
their properties in the bulk or consolidated state. In a bulk state, the CNT, as a rule,
does not conduct an electric current, but with a slight compression, the situation is
changing.
The properties of an array of carbon nanotubes or a material containing CNT
differ from the properties of individual nanotubes (single-layered or multilayered).
An array of CNTs, unlike individual nanotubes, may not conduct an electric current.
This is due to the fact that the connections between adjacent nanotubes are van der
Waals.
Adding a small amount of CNT to a dielectric matrix facilitates the appearance
of electrical conductivity [1–6], whose size has a wide range. This dispersion in
the magnitude of electrical conductivity is reflected by the complex interaction of
various factors, the most important of which are the own conductivity of CNTs and
their contact resistance.
The electrical conductivity of the individual BWNT is 10
4 –10
7 (m)
−1 [7–9], the
measured contact resistance for the SCNT bundle is 100–400 k for metal/metal or
semiconductor/semiconductor compounds and twice that for metal/semiconductor
systems [10].
Defects in CNT may occur during synthesis (growth defects) or during external
influences, for example, high-energy irradiation.
Experimentally obtained nanostructures may contain defects that lead to the
distortion of their structure and differences in properties. The formation of curved,
colloid, swirling CNTs, as well as tubes of variable diameters occur only in the presence of topological defects associated with re-hybridization and unsaturated bonds
[11].
Topological defects can disappear when heated to a temperature of up to 2773 K
and higher in an inert medium.
In nanostructured materials, the peculiarity of the atomic structure is that each
element of the system or nanocomposite has a local structure of the free volume,
which leads to the appearance of potential barriers limiting the charge carriers in
the 1-to-2D (interlayer intervals of MCNT) on the boundary, 2-to-1D (in CNT) or
3-to-0D (fullerenes in the matrix and isolated clusters) directions, and the electronic
processes are predominantly quantum in nature.