We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale.

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Two-dimensional atomic crystals

CARBON nanotubes1 are expected to have a wide variety of interesting properties. Capillarity in open tubes has already been demonstrated2–5, while predictions regarding their electronic structure6–8 and mechanical strength9 remain to be tested. To examine the properties of these structures, one needs tubes with well defined morphologies, length, thickness and a number of concentric shells; but the normal carbon-arc synthesis10,11 yields a range of tube types. In particular, most calculations have been concerned with single-shell tubes, whereas the carbon-arc synthesis produces almost entirely multi-shell tubes. Here we report the synthesis of abundant single-shell tubes with diameters of about one nanometre. Whereas the multi-shell nanotubes are formed on the carbon cathode, these single-shell tubes grow in the gas phase. Electron diffraction from a single tube allows us to confirm the helical arrangement of carbon hexagons deduced previously for multi-shell tubes1.

Single-shell carbon nanotubes of 1-nm diameter

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

Pores of molecular dimensions can adsorb large quantities of gases owing to the enhanced density of the adsorbed material inside the pores1, a consequence of the attractive potential of the pore walls. Pederson and Broughton have suggested2 that carbon nanotubes, which have diameters of typically a few nanometres, should be able to draw up liquids by capillarity, and this effect has been seen for low-surface-tension liquids in large-diameter, multi-walled nanotubes3. Here we show that a gas can condense to high density inside narrow, single-walled nanotubes (SWNTs). Temperature-programmed desorption spectrosocopy shows that hydrogen will condense inside SWNTs under conditions that do not induce adsorption within a standard mesoporous activated carbon. The very high hydrogen uptake in these materials suggests that they might be effective as a hydrogen-storage material for fuel-cell electric vehicles.

Storage of hydrogen in single-walled carbon nanotubes

Nanotubes from Carbon.

A semiconductor device is provided which is produced from a high-quality and large-area graphene substrate and is capable of fully exhibiting superior electronic properties that graphene inherently has. The semiconductor device is capable of realizing increased operation speed, reduced power consumption, and higher degree of integration, and thus is capable of improving the reliability and productivity. Electrical short circuit between a graphene layer ( 4 ) and a metal catalyst layer for growth of graphene is prevented by causing the metal catalyst layer to be absorbed as a compound/alloyed layer 5 at the interface between a substrate ( 1 ) and an oxide layer ( 2 ).

Substrate, manufacturing method of substrate, semiconductor element, and manufacturing method of semiconductor element

Semiconductor graphene is employed as a channel layer, metal graphene is employed as each electrode layer of source, drain and gate also serving as an interconnection, and an oxide is employed as a gate insulating layer. The channel layer and the electrode layer are arranged on the same plane.

Semiconductor device employing graphene and method for fabricating the same

In order to distinguish between the role of intra- and inter-molecular phonons in the mechanism of C 60 superconductors, the dopant isotope effect has been studied for the Rb 3 C 60 superconductor using three different samples: 85 Rb, 87 Rb and natural Rb isotopic composition. Unlike the carbon isotope effect, changing the mass of the Rb dopant does not change the superconductive onset temperature T c of the material beyond experimental error. From these results it is concluded that the active phonons in the superconductivity are of intra-molecular and not of inter-molecular nature.

Dopant isotope effect on superconductivity in Rb3C60

Provided is a graphene substrate, which is manufactured by: bringing a metal layer into contact with a carbon-containing layer and heating the metal layer to dissolve carbon in the carbon-containing layer into the metal layer; and cooling the metal layer to precipitate the carbon in the metal layer as graphene on any substrate surface.

Method of manufacturing graphene substrate, and graphene substrate

PURPOSE: To efficiently and simply produce an opened nanotube and a high quality purified nanotube. CONSTITUTION: A reaction reagent selected from among an oxidizing agent, a nitration agent and a sulfonating agent and a carbon.nanotube is mixed in a liq. phase to produce a treated carbon.nanotube which is opened by various chemical reactions under moderate conditions, and the nanotubes introduced with various functional groups such as nitro (NO 2 ), sulfoneate (SO 3 H), carboxyl (COOH), carbonyl (C=O), ether (C-O-C) and phenolic hydroxide (OH) are produced. A carbon impurity other than the carbon.nanotube is decomposed at similar condition to purify the carbon.nanotube. COPYRIGHT: (C)1996,JPO

Hidefumi Hiura

Papers

Substrate, manufacturing method of substrate, semiconductor element, and manufacturing method of semiconductor element

Semiconductor device employing graphene and method for fabricating the same

Dopant isotope effect on superconductivity in Rb3C60

Method of manufacturing graphene substrate, and graphene substrate

Purifying-opening method of carbon-nanotube in liquid phase and introducing method of functional group