An investigation into the electrical properties of finite carbon nanotubes in the presence of polar molecules

This study employs quantum transport theory to investigate the electrical properties of zigzag carbon nanotubes with different hopping integrals. It is found that the current-bias voltage profiles have a step-like form, in which each step corresponds to the voltage bias at which the energy imparted to the electrons is sufficient to cause them to hop between neighboring atoms. In carbon nanotubes with a length of several nanometers, the normalized-current-voltage profiles exhibit prominent peaks as the hopping integral decreases and distinct troughs as the hopping integral increases. In longer nanotubes, the current changes by several orders of magnitude in these peak and trough regions of the current–voltage curves. Furthermore, the peaks and troughs appear at lower values of the bias voltage. The results presented in this study suggest that semi-conducting zigzag nanotubes with an appropriate bias have the potential for use as ion or polar molecule absorption sensors.