Carbon Nanotubes (CNTs) are cylindrical shells made, in concept, by rolling graphene sheets into a seamless cylinder. CNTs exist as either single-wall nanotubes (SWNTs) or multi-walled nanotubes (MWNTs). The SWNT consists of a single graphene sheet, which is a planar array of benzene molecules, involving only hexagonal rings with double and single carbon-carbon bonding. The choice of rolling axis relative to the hexagonal network of the graphene sheet and the radius of the closing cylinder allows for different types of SWNTs, which vary from insulating to conducting¹. Figures 1a, 1b, and 1c show SWNTs of three different types²: armchair, zigzag, and chiral. The twist of the chiral nanotube is clearly evident in the lower Fig. 1c, a perspective view along the tube axis, and in Fig. 1d, a scanning probe microscope (SPM) picture of a chiral SWNT³. MWNTs comprise an array of such nanotubes that are concentrically nested. A transmission electron microscope (TEM) image of a nine-walled CNT is shown in Fig. 1e. CNTs with perfect crystalline structure are straight cylinders.