posted on 2019-12-31, 16:19authored byDekel Nakar, Georgy Gordeev, Leonardo D. Machado, Ronit Popovitz-Biro, Katya Rechav, Eliezer F. Oliveira, Patryk Kusch, Ado Jorio, Douglas S. Galvão, Stephanie Reich, Ernesto Joselevich
While various electronic components based on carbon nanotubes
(CNTs)
have already been demonstrated, the realization of miniature electromagnetic
coils based on CNTs remains a challenge. Coils made of single-wall
CNTs with accessible ends for contacting have been recently demonstrated
but were found unsuitable to act as electromagnetic coils because
of electrical shorting between their turns. Coils made of a few-wall
CNT could in principle allow an insulated flow of current and thus
be potential candidates for realizing CNT-based electromagnetic coils.
However, no such CNT structure has been produced so far. Here, we
demonstrate the formation of few-wall CNT coils and characterize their
structural, optical, vibrational, and electrical properties using
experimental and computational tools. The coils are made of CNTs with
2, 3, or 4 walls. They have accessible ends for electrical contacts
and low defect densities. The coil diameters are on the order of one
micron, like those of single-wall CNT coils, despite the higher rigidity
of few-wall CNTs. Coils with as many as 163 turns were found, with
their turns organized in a rippled raft configuration. These coils
are promising candidates for a variety of miniature devices based
on electromagnetic coils, such as electromagnets, inductors, transformers,
and motors. Being chirally and enantiomerically pure few-wall CNT
bundles, they are also ideal for fundamental studies of interwall
coupling and superconductivity in CNTs.