W. Mickelson

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.

Transformation of BxCyNz nanotubes to pure BN nanotubes

We demonstrate that multiwalled BxCyNz nanotubes can be efficiently converted to BN multiwalled nanotubes via an oxidation treatment. The microstructure and composition of the precursors and final products have been characterized by high-resolution transmission electron microscopy, electron energy-loss spectroscopy, and energy dispersive x-ray spectroscopy. The conversion process is monitored by thermogravimetric analysis. Carbon layers of BxCyNz nanotubes start to oxidize at 550 °C, thereby transforming BxCyNz nanotubes into pure BN nanotubes. The remarkable thermal stability of pure BN nanotubes in an oxidizing environment is also established.

A Carbon Nanotube-based NEMS Parametric Amplifier for Enhanced Radio Wave Detection and Electronic Signal Amplification

We propose a scheme for a parametric amplifier based on a single suspended carbon nanotube field-emitter. This novel electromechanical nanotube device acts as a phase-sensitive, variable-gain, band-pass-filtering amplifier for electronic signal processing and, at the same time, can operate as a variable-sensitivity, tuneable detector and transducer of radio frequency electromagnetic waves. The amplifier can exhibit infinite gain at pumping voltages much less than 10 Volts. Additionally, the amplifiers low overhead power consumption (10-1000 nW) make it exceptionally attractive for ultra-low-power applications.

Low power microheater-based combustible gas sensor with graphene aerogel catalyst support

This paper reports a microheater-based combustible gas sensor with ultra-low power consumption (1.4 mW) using pulsed heating and novel sensing materials. High surface area graphene aerogel is used as a support for platinum and palladium nanoparticles. Pulsed heating (450 °C) at a 10% duty cycle yields an order of magnitude reduction in power consumption with no loss of sensitivity. Sensing response to hydrogen and propane gas shows promising selectivity and order of magnitude faster response and recovery times (1-2 s) compared to previous work. The results indicate a high level of flexibility in creating selective, low power combustible gas sensors using this microheater platform and catalytic material system.

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