Super square carbon nanotube networks: mechanical properties and electric conductivity

Super square carbon nanotube (SSCNT) lattice is a class of CNT networks that have unique mechanical and electrical conductivity properties and can be applied in various modern devices. Two possible supercells of the SSCNT structure with minimal sizes of a “window” were obtained in the result of mathematical modeling. These supercells, called SSCNT-I and SSCNT-II, are distinguished by their topology and the number of non-hexagonal elements. On the basis of the analysis of stress-strain state curves, it was established that the structure SSCNT-I with a smaller number of defects was stronger. 2D films with experimental dimensions were obtained by translation of supercells SSCNT-I and SSCNT-II. The resistances of these films were calculated using the non-equilibrium Green function (NEGF) method: for SSCNT-I these values equaled 18.13 kΩ in the Z direction and 42.74 kΩ in the Y direction, for SSCNT-II — 65.86 kΩ in the Z direction and 60.17 kΩ in the Y direction. The better conductivity of the structure with supercells SSCNT-I along both directions can be explained by a less number of defects. Together with the better heat of formation and mechanical strength, it can be concluded that films composed of SSCNT-I are more suitable for application in electronic devices. Calculations show that the resistance of SSCNT films is higher than the resistance of CNT in 4 –10 times, but they allow placing electrodes in both vertical and horizontal directions that may be important for their use in wearable electronics devices.