Two-dimensional thermal conductivity of defect-free single-walled carbon nanotubes

Based on the known Debye’s model for heat capacity and on the kinetic model for the phonon heat transfer taking into account the length of nanotube and also of the contribution made by phonon-phonon scattering, a heat conduction model of defect-free single-wall carbon nanotube was proposed. Based on this model, the dependences of the two-dimensional thermal conductivity of defect-free single-wall carbon nanotubes on their length and temperature were defined

Influence of sputtering atmosphere on hopping conductance in granular nanocomposite (FeCoZr)x(Al2O3)1−x films

The present paper investigates conductivity σ for a wide temperature range of 2 K < T < 300 K in the nanocomposite (FeCoZr)x(Al2O3)1−x films (1–6 μm thicknesses, 0.30 < x < 1.00) which were sputtered on glass–ceramic substrates from the compound target in vacuum chamber filled with Ar (set 1 films) or Ar + O2 gas mixture (set 2 films). TEM and HRTEM images revealed that granular films of set 1 containing nanosized crystalline metallic bcc α-FeCo-based nanoparticles embedded in the amorphous Al2O3 matrix. In case of Ar + O atmosphere of deposited α-FeCo-based crystalline “cores” with stabilized sizes were covered with an amorphous FeCo-based oxide “shells”. The σ(T) dependences were found to be in agreement with this phase structure. They show transition of the set 1 films σ(T) curves with x from tunneling (hopping) behavior below the percolation threshold x < xC ≈ 0.46 to metallic one for x > xC. Moreover, as opposed to such behavior, for the set 2 films hopping mechanism of σ(T) was revealed far beyond xC due to the formation of semiconducting FeCo-based oxide “shells” separating electrically contacting FeCoZr cores

Controlling the characteristics of photovoltaic cells based on their own semiconductors

The features of photovoltaic cells with their own photoconductivity in semiconductors with deep-level multiply-charge impurity have been considered. The use of such structures can significantly extend the dynamic range of sensitivity and gain new functional properties of single-element photoelectric receivers. Photovoltaic converters based on semiconductors with deep-level multiply-charge acceptor type impurity enable devices with a wider functionality, whereas the structure with multiply-charge donor type impurity has better linearity of energy performance. In the development of photoelectric receiver with advanced functionality features the model of recombination processes in multiply-charge impurity in a wide range of optical radiation power density has been used