Carbon nanotubes: nanomechanics, manipulation, and electronic devices

Abstract

Carbon nanotubes are novel materials with unique electrical and mechanical properties. Here we present results on their atomic structure and mechanical properties in the adsorbed state, on ways to manipulate individual nanotubes, on their electrical properties and, finally, on the fabrication and characteristics of nanotube-based electron devices. Specifically, Ž . atomic force microscopy AFM and molecular mechanics simulations are used to investigate the effects of van der Waals interactions on the atomic structure of adsorbed nanotubes. Both radial and axial structural deformations are identified and the interaction energy itself is obtained from the observed deformations. The conditions under which the structure of a nanotube will adjust to the topography of the substrate are defined. We show that the strong substrate-nanotube interaction allows the manipulation of both the position and shape of individual nanotubes at inert surfaces using the AFM. AFM manipulation is then utilized to position individual nanotubes on electrical pads so that their electrical characteristics can be evaluated. We demonstrate the operation of a field-effect transistor based on a single semiconducting nanotube and of a single-electron transistor using a nanotube bundle as Coulomb island. Finally, conducting nanotubes are employed as tips for AFM lithography. q

Strain energy and lateral friction force distributions of carbon nanotubes manipulated into shapes by atomic force microscopy

“…In future CNT-based circuit applications [11], the band structure of the SWCNT will be fined-tuned by adjusting the flexural strain energy [12]. Because chemical reactivity is related to local strain, the sensitivity of CNTs used for chemical sensors will likely increase by simply optimizing their shape.…”

Niobium and niobium nitride SQUIDs based on anodized nanobridges made with an atomic force microscope

“…As an example, one can cite the tip indentation patterning that takes advantage of the local tip-surface mechanical interaction leading to a surface scratching [4][5][6]). Another technology is given by the local electrochemical oxidation of the surface using a voltage biased tip [9][10][11][12][13][14][15][16][17]. In this paper, we will focus on this latter technique although SQUIDs have been successfully obtained using the former one [6].…”

“…Quantum point contacts on a 2D electron gas [8] or in metal [10], nanowires [9], single electron devices [11,17], superconducting devices [13] as well as other nanoscale devices involving nanotubes [14] or clusters [15] have been obtained with this technique.…”

Mechanical properties of connected carbon nanorings via molecular dynamics simulation

“…[21][22][23] In parallel with these computational studies of stability, nanorings have been experimentally fabricated by a number of researchers. [25][26][27][28][29] As shown in Fig. 1, such nanorings have also been observed to form in linked arrangements.…”

“…1, such nanorings have also been observed to form in linked arrangements. 28 Based on their size, most of the nanorings observed must be composed of multiwall nanofibers, but there is some indication that perfect nanotori are formed as well.…”