A carbon nanotubes are cylindrical sheets of carbon that were discovered in 1991. Nanotubes have diameters of about 1 nm and lengths up to a few centimeters. Because of their small size and amazing physical properties, nanotubes have been a popular subject for condensed matter physics research as well as a top candidate for applications in nanotechnology.

Quick Facts about Carbon Nanotubes

• Carbon nanotubes can have tensile strengths 60 times larger than steel
   

• Several nanotubes of differing diameter can form nested structures called multiwalled nanotubes
  
   

• Carbon nanotubes can be either a metal or semiconductor
   

• Some nanotubes can support electrical current densities 1000 times higher than those in copper and silver
   

• Nanotubes can exhibit ballistic conduction where current carriers flow without collision