Radial Electromechanical Properties of Carbon Nanotubes

摘要

Single-walled carbon nanotubes (SWNTs) have been the aim of intensive research over the last years because of their unusual electrical and mechanical properties. Both properties are also closely related since there are strong indications that changes in the electrical conductance of the molecules can be induced by mechanical deformations. These effects have clear potential applications in the design and construction of electronic devices based on carbon nanotubes. In this work we present an experimental study of the electrical conductance of single-walled carbon nanotubes as a function of the loading force and bias voltage applied by an atomic force microscope tip used as a mobile electrode. For SWNTs, as the force applied to the nanocontact is increased, we observe first an increase in the low-voltage conductance (LVC) due to the tip-SWNT electrical contact formation, and second, an irreversible drop of the conductance at high loading forces due to radial molecule deformation. Conversely, the high-voltage conductance (HVC) is insensitive to tip load. We suggest this technique as a possible way to tailor the conductivity of a circuit based on single-walled carbon nanotubes.