Persons

Two-dimensional (2D) Janus-type materials XMoSiN2 (X = S, Se or Te) are characterized by high values of binding energy and strong built-it field allowing the separation of generated electron-hole pairs within a single layer. These 2D materials are promising for photovoltaic applications. In this work, nanotubes of small diameters based on 2D Janus-type materials SMoSiN2, constructed and optimized, are considered in the framework of modeling. Using density functional theory calculations, the band structures and optical absorption spectra of these nanotubes with different chalcogen arrangements have been obtained. For the considered structures, a wide region of absorption of short-wavelength radiation is observed under tube deformation ε = 12.46 %. XMoSiN2 Janus-type nanotubes act as semiconductors, the electronic and optical properties of which can be controlled by tube deformation.

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The hybrid systems based on the carbon nanotubes (CNT) and fullerenes (nanopipodes) are promising for applications in nanoelectronics. With insignificant variation of the CNT diameter the change of the fullerenes geometry takes place. The periodically located inside fullerenes represent a set of quantum points in the one-dimensional super-lattice. Using the variation of inside fullerenes it is possible to modulate the zone structure of the CNT - fullerene system and to control the electronic and phonon characteristics of nanopipodes. In the work the optical and thermoelectric properties of CNT with encapsulated molecules of C fullerene have been investigated. Using the first-principle methods the coefficients of absorption, optical conductivity, thermal conductivity, thermoelectric figure of merit for CNT with fullerenes, periodically located inside the nanotubes at different distances from each other, have been calculated. It has been shown that with decreasing the distance between fullerenes the optical conductivity of CNT - C is suppressed at high frequencies. It has been determined that the conductance of the structures with fullerenes is less than the conductance of a clean tube, and approximately equal for considered distances (12.3 and 19.7 Å) between fullerenes. The CNT thermal conductivity due to the encapsulation of fullerenes considerably (3-4 times) decreases for the considered CNT (8.8) - C systems.

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