In nanotechnology or the building of extremely small machines and computers, a nanotube (sometimes called a buckytube) is a long, cylindrical carbon structure consisting of hexagonal graphite molecules attached at the edges. The nanotube was developed from the so-called Fullerene, a structure similar to the way geodesic domes, originally conceived by R. Buckminster Fuller are built. Hence, nanotubes are sometimes called buckytubes.
Some nanotubes have a single cylinder; others have two or more concentric cylinders. Nanotubes have several characteristics: wall thickness, number of concentric cylinders, cylinder radius, and cylinder length. Some nanotubes have a property called chirality, an expression of longitudinal twisting. Researchers have suggested several applications for nanotubes. The structures might be assembled into microscopic mechanical systems called nanomachines. Because graphite can behave as a semiconductor, nanotubes might be used to build microscopic resistors, capacitors, inductors, diodes, or transistors. Concentric nanotubes might store electric charges because of capacitance among the layers, facilitating the construction of high-density memory chips. (see – Fullerene)