Koda V. Electronic building and electromechanical properties of carbon nanotubes

The thesis deals with the atomic structure, elastic properties of carbon nanotubes and relationship of the electronic structure of defects in them with the electrical conductivity. The mechanism of layer growth of carbon nanotubes in the pores of anodized aluminum oxide is studied. The elastic properties of individual nanotubes in the radial direction are investigated. The reverse nonlinear dependence of elasticity coefficient on CNT's diameter is set. Young's modulus of CNT in the radial direction, which yields an order of longitudinal Young's modulus of nanotubes, is calculated. Using positron spectroscopy, CNTs with different defects are investigated. The direct relationship between ?-electron wave function localization and concentration of free charge carriers is obtained. We show that appearing of defects such as edge dislocation lead to increasing of conductive electron concentration. In the thesis the influence of mechanical deformation on the conductivity of arrays of carbon nanotubes and their composites with thermo expanded graphite is studied. According to the electrical conductivity measurement of multilayer carbon nanotube array in a finitive volume during compression deformation and subsequent unloading, direct and reverse percolation "insulator-metal" transitions are detected. We encountered a giant (400%) elastic relaxation of nondirectional carbon nanotubes during their unloading after the previous compression by piston.