The use of individual molecules as functional electronic devices was first proposed in the 1970s (ref 1) Since then, molecular electronics2,3 has attracted much interest, particularly because it could lead to conceptually new miniaturization strategies in the electronics and computer industry The realization of single-molecule devices has remained challenging, largely owing to difficulties in achieving electrical contact to individual molecules Recent advances in nanotechnology, however, have resulted in electrical measurements on single molecules4,5,6,7 Here we report the fabrication of a field-effect transistor—a three-terminal switching device—that consists of one semiconducting8,9,10 single-wall carbon nanotube11,12 connected to two metal electrodes By applying a voltage to a gate electrode, the nanotube can be switched from a conducting to an insulating state We have previously reported5 similar behaviour for a metallic single-wall carbon nanotube operated at extremely low temperatures The present device, in contrast, operates at room temperature, thereby meeting an important requirement for potential practical applications Electrical measurements on the nanotube transistor indicate that its operation characteristics can be qualitatively described by the semiclassical band-bending models currently used for traditional semiconductor devices The fabrication of the three-terminal switching device at the level of a single molecule represents an important step towards molecular electronics

Room-temperature transistor based on a single carbon nanotube

The major part of this chapter has already appeared in [1], but because of the length restrictions (in Science), the discussion on why we think this form is given in only brief detail. This chapter goes into more depth to try to answer the questions of why the fullerenes form themselves. This is another example of the very special behavior of carbon. From a chemist’s standpoint, it is carbon’s ability to form multiple bonds that allows it to make these low dimensional forms rather than to produce tetrahedral forms. Carbon can readily accomplish this and it is in the mathematics and physics of the way this universe was put together, that carbon is given this property. One of the consequences of this property is that, if left to its own devices as carbon condenses from the vapor and if the temperature range is just right, above 1000°C, but lower than 1400°C, there is an efficient self-assembly process whose endpoint is C60.

https://science.sciencemag.org/content/sci/273/5274/483.full.pdf

Crystalline Ropes of Metallic Carbon Nanotubes

https://www.bc.edu/content/dam/files/schools/cas_sites/physics/pdf/Ren/p85.pdf

Advances in the science and technology of carbon nanotubes and their composites: a review

Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Chemistry of Carbon Nanotubes

Small but strong: A review of the mechanical properties of carbon nanotube–polymer composites

CARBON exhibits a unique ability to form a wide range of structures. In an inert atmosphere it condenses to form hollow, spheroidal fullerenes. Carbon deposited on the hot tip of the cathode of the arc-discharge apparatus used for bulk fullerene synthesis will form nested graphitic tubes and polyhedral particles. Electron irradiation of these nanotubes and polyhedra transforms them into nearly spherical carbon 'onions'. We now report that covaporizing carbon and cobalt in an arc generator leads to the formation of carbon nanotubes which all have very small diameters (about 1.2 nm) and walls only a single atomic layer thick. The tubes form a web-like deposit woven through the fullerene-containing soot, giving it a rubbery texture. The uniformity and single-layer structure of these nanotubes should make it possible to test their properties against theoretical predictions.

Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls

Encapsulating atoms or molecules inside fullerene cages could give rise to a myriad of novel molecules and materials. The existence of such species is now strongly supported by a growing body of experimental evidence. Fullerene& ndash;metal complexes generally thought to be endohedral are being produced and purified in milligram quantities, and their structure and properties are beginning to be explored

Atoms in carbon cages: the structure and properties of endohedral fullerenes

Electron diffraction patterns of the fullerene C 60 in the gaseous state have been obtained by volatilizing it from a newly designed oven-nozzle at 730°C. The many peaks of the experimental radial distribution curve calculated from the scattered intensity are completely consistent with icosahedral symmetry for the free molecule. On the basis of this symmetry assumption, least-squares refinement of a model incorporating all possible interatomic distances led to the values r g (C 1 -C 2 ) = 1.458(6) angstroms (A) for the thermal average bond length within the five-member ring (that is, for the bond fusing five- and six-member rings) and r g (C 1 -C 6 ) = 1.401(10) A for that connecting five-member rings (the bond fusing six-member rings). The weighted average of the two bond lengths and the difference between them are the values 1.439(2) A and 0.057(6) A, respectively. The diameter of the icosahedral sphere is 7.113(10) A. The uncertainties in parentheses are estimated 2σ values.

https://science.sciencemag.org/content/sci/254/5030/410.full.pdf

Bond lengths in free molecules of buckminsterfullerene, c60, from gas-phase electron diffraction.

RECENT developments in the synthesis of macroscopic amounts of the C60 and C70 carbon clusters1–3 have made possible spectroscopic1,2,4–7 studies of these species. Infrared1,2 and vibrational Raman4 spectra strongly support the proposed 'soccer ball' structure for the C60 cluster8, and NMR spectroscopy directly confirms its icosahedral symmetry5,6. Here we present images of C60 clusters obtained with the scanning tunnelling microscope. These species are roughly spherical and form mobile hexagonal arrays on a Au(lll) surface with an intercluster spacing of 11.0 A Brighter features evident in the arrays are tentatively identified as C70 clusters.

Imaging C 60 clusters on a surface using a scanning tunnelling microscope

The vibronic spectrum of laser desorbed and jet cooled guanine consists of bands from three different tautomers of guanine as revealed by UV–UV and IR–UV double resonance spectroscopy. 1-methylguanine, in which the Keto–Enol tautomerism is blocked, shows hole burning spectra from the 9H-and 7H-Keto form. A comparison of the vibronic pattern of the different tautomers demonstrates that the vibronic spectrum built on the redmost guanine band at 32 870 cm−1 (electronic origin 0) can be traced back to the 9H-Enol tautomer, while the spectra built on the origins at 0+404 cm−1 and 0+1044 cm−1 stem from the two Keto tautomers. The IR–UV double resonance spectra of the OH-and NH-stretch vibrations of the different tautomers support this assignment. The UV and IR spectra can be partly assigned by comparison with ab initio calculated vibrational frequencies and with the help of deuteration experiments.

/pdf/guanine-tautomerism-revealed-by-uv-uv-and-ir-uv-hole-burning-3o78o5r4y2.pdf

M.S. de Vries

Papers

Cobalt-catalysed growth of carbon nanotubes with single-atomic-layer walls

Atoms in carbon cages: the structure and properties of endohedral fullerenes

Bond lengths in free molecules of buckminsterfullerene, c60, from gas-phase electron diffraction.

Imaging C 60 clusters on a surface using a scanning tunnelling microscope

Guanine tautomerism revealed by UV–UV and IR–UV hole burning spectroscopy