Carbon nanotubes (CNTs) were first discovered by Iijima in 1991 [1]. CNTs have sparked great interest in many scientific fields such as physics, chemistry, and electrical engineering [2, 3]. CNTs are composed of graphene sheets rolled into closed concentric cylinders with diameter of the order of nanometers and length of micrometers. CNTs are in two kinds, based on number of walls, the single-w...