Adam Michael Fennimore

Rotational actuators based on carbon nanotubes.

Nanostructures are of great interest not only for their basic scientific richness, but also because they have the potential to revolutionize critical technologies. The miniaturization of electronic devices over the past century has profoundly affected human communication, computation, manufacturing and transportation systems. True molecular-scale electronic devices are now emerging that set the stage for future integrated nanoelectronics. Recently, there have been dramatic parallel advances in the miniaturization of mechanical and electromechanical devices. Commercial microelectromechanical systems now reach the submillimetre to micrometre size scale, and there is intense interest in the creation of next-generation synthetic nanometre-scale electromechanical systems. We report on the construction and successful operation of a fully synthetic nanoscale electromechanical actuator incorporating a rotatable metal plate, with a multi-walled carbon nanotube serving as the key motion-enabling element.

Precision cutting of nanotubes with a low-energy electron beam

We report on a method to locally remove material from carbon and boron nitride nanotubes using the low-energy focused electron beam of a scanning electron microscope. Using this method, clean precise cuts can be made into nanotubes, either part-way through (creating hingelike geometries) or fully through (creating size-selected nanotube segments). This cutting mechanism involves foreign molecular species and differs from electron-beam-induced knock-on damage in transmission electron microscopy.

Imaging the life story of nanotube devices

Live imaging of operating multiwall carbon nanotube (MWCNT-) based electronic devices is performed by high resolution transmission electron microscopy. Our measurements allow us to correlate electronic transport with changes in device structure. Surface contamination, contact annealing, and sequential wall removal are observed. Temperature profiles confirm diffusive conduction in MWCNTs in the high bias limit. This technique provides a general platform for studying nanoscale systems, where geometric configuration and electronic transport are intimately connected.

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

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.

Engineering Nanomotor Components from Multi‐Walled Carbon Nanotubes via Reactive Ion Etching

It has been shown that a multi‐walled carbon nanotube (MWCNT) can be used as the rotation enabling element for nanoelectromechanical systems. Modification of the MWCNT to create a rotational bearing in previous devices has concentrated on smaller diameter tubes and mechanical methods to create the bearing. We here investigate reactive ion etching of a MWCNT as a means to engineer nanomotor components, including the rotational bearing.

Electrically Driven Vaporization Of Multiwall Carbon Nanotubes For Rotary Bearing Creation

We have previously reported on the creation of nanoscale rotational actuators based on multiwall carbon nanotubes. During the fabrication of these devices, we torsionally sheared the outer walls of the MWCNT to form a rotational bearing. We have designed an alternate technique for forming a rotational bearing geometry using electrically driven vaporization (EDV) of multiwall nanotube shells. While applying this technique, we have discovered an interesting failure mode.

Erratum: “Precision cutting of nanotubes with a low-energy electron beam” [Appl. Phys. Lett. 86, 053109 (2005)]

Erratum: “Precision cutting of nanotubes with a low-energy electron beam” †Appl. Phys. Lett. 86, 053109 „2005...‡ T. D. Yuzvinsky, A. M. Fennimore, W. Mickelson, C. Esquivias, and A. Zettl Department of Physics, University of California at Berkeley, and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 Received 8 June 2005; accepted 23 June 2005; published online 3 August 2005 DOI: 10.1063/1.2000345