Discovery of single walled and multi walled carbon nanotubes opened up the possibility of numerous nanotube applications in the field of fullerene science and technology.
Carbon atoms also arrange themselves in hexagonally bonded array in tube form to create many centimeters long buckytubes or nanotubes. Chirality is defined by a single vector called the Chiral vector or C = na1 + ma2, where a1 and a2 are the unit cell base vectors and n,m assume different values for each type of tube. Based on the chirality, the graphene sheet can be rolled to form zigzag, armchair and chiral nanotubes.
There are many possible ways to form a cylinder with a graphene sheet, rolling it along one of the symmetry axis gives symmetrical tubes i.e., either a zigzag tube or an armchair tube and rolling it along non-symmetrical axis gives chiral nanotubes.
The electronic properties of a nanbotube changes in correspondence with the axis of symmetry along which it is rolled, armchair are metallic while zigzag and chiral can be either metallic or a semiconductor.