Showing papers by "Andras Kis published in 2006"

Interlayer forces and ultralow sliding friction in multiwalled carbon nanotubes.

Abstract: We describe interlayer force measurements during prolonged, cyclic telescoping motion of a multiwalled carbon nanotube. The force acting between the core and the outer casing is modulated by the presence of stable defects and generally exhibits ultralow friction, below the measurement limit of 1.4 x 10(-15) N/atom and total dissipation per cycle lower than 0.4 meV/atom. Defects intentionally introduced in the form of dangling bonds lead to temporary mechanical dissipation, but the innate ability of nanotubes to self heal rapidly optimizes the atomic structure and restores smooth motion.

Shrinking a carbon nanotube.

Abstract: We report a method to controllably alter the diameter of an individual carbon nanotube. The combination of defect formation via electron irradiation and simultaneous resistive heating and electromigration in vacuum causes the nanotube to continuously transform into a high-quality nanotube of successively smaller diameter, as observed by transmission electron microscopy. The process can be halted at any diameter. Electronic transport measurements performed in situ reveal a striking dependence of conductance on nanotube geometry. As the diameter of the nanotube is reduced to near zero into the carbon chain regime, we observe negative differential resistance.

Controlled placement of highly aligned carbon nanotubes for the manufacture of arrays of nanoscale torsional actuators

Abstract: We have fabricated ordered arrays of nanoscale torsional actuators consisting of metal mirrors bonded to precisely oriented multiwall carbon nanotubes. The fabrication is facilitated by a new nanotube positioning method which employs localized electron beam activation of polymer residue on a silicon oxide surface.