At the Lawrence Berkeley National Laboratory, researchers are working under the direction of Professor of Physics Alex Zettl to turn carbon nanotubes (CNTs) into conveyor belts that transport atom-size particles to microscopic worksites. The tiny conveyor belt has many potential uses for delivery of mass one atom at a time, including in nanofabrication for nanosoldering and in nanoelectromechanical devices, says Chris Regan, one of the researchers. The scientist began by thermally evaporating indium metal onto a bundle of CNTs, which resulted in isolated indium crystals settling on the surfaces of tubes instead of creating a uniform layer. The bundle was then put inside a transmission electron microscope, and the free end of the nanotube made contact with a tungsten tip. Voltage was applied between tip and the other end of the nanotube to produce a circuit that created an electrical current in the tube to heat the indium particles. Various other reactions occurred when thermal energy and voltage were controlled, and a real-time video of the nanotube surface was made, showing that an indium particle disappeared, and that a contiguous one got bigger. The indium atoms continued to move forward along the tube until they all gathered at its end, and increased speed was seen in particle movement. Reversing the current direction reverses the direction of atomic transport so that indium particles continuously moved back and forth and maintained all atoms in transit.