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Direct growth of aligned metal composite carbon nanofibers (MCNFs) was achieved by a highly reproducible room temperature growth process on cost effective electrically conductive copper (Cu) substrate without any catalyst. The direct fabrication of MCNFs on electrically conductive substrate might offer new perspectives in the field of field emission displays (FEDs)., (© The Royal Society of Chemistry 2011)

Here, we reveal the growth process of single and few-layer graphene crystals in the solid carbon source based chemical vapor deposition (CVD) technique. Nucleation and growth of graphene crystals on a polycrystalline Cu foil are significantly affected by the injection of carbon atoms with pyrolysis rate of the carbon source. We observe micron length ribbons like growth front as well as saturated growth edges of graphene crystals depending on growth conditions. Controlling the pyrolysis rate of carbon source, monolayer and few-layer crystals and corresponding continuous films are obtained. In a controlled process, we observed growth of large monolayer graphene crystals, which interconnect and merge together to form a continuous film. On the other hand, adlayer growth is observed with an increased pyrolysis rate, resulting few-layer graphene crystal structure and merged continuous film. The understanding of monolayer and few-layer crystals growth in the developed CVD process can be significant to grow graphene with controlled layer numbers. [ABSTRACT FROM AUTHOR]

We demonstrate a unique strategy to fabricate highly transparent and flexible field electron emitters (FEEs) based on combined carbon nanostructures, i.e., conical nanocarbon structures (CNCSs) and single-walled carbon nanotubes (SWNTs). The combined structure was prepared by spray coating of 1,2-dichloroethane (DCE) dispersed SWNTs onto neon ion (Ne+) irradiation induced CNCSs on nafion substrate. The field emission (FE) property of SWCNTs on both flat nafion and CNCSs surfaces increased with increasing the SWCNTs amount. The best FE result was attained for the highest amount of SWCNTs on the CNCSs substrate. This kind of collective structures is found to be effective emitters on transparent and flexible ion-irradiated nafion substrate. Moreover, the combined carbon nanostructures showed improved transparency and emission performance compared to the individual nanostructures. The FE properties of 0.5 ml SWCNTs solution on CNCSs surfaces were equal to those of 1.5 ml SWCNTs solution on flat nafion surface. The hybrid structure based emitters (CNCSs and SWCNTs) produced by this method are lower-cost cathode materials than hybrid structures of SWCNTs and flat nafion. Thus the combined nanostructures of SWCNTs/CNCSs might have huge prospects for the fabrication of efficient transparent and flexible FEEs and their broad application in next-generation portable display devices. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The 4 in. wafer-scale production of probes tipped with single carbon nanofibers (CNF probes) for scanning probe microscope was achieved by an Ar+-ion-irradiation method. For the wafer-scale production, an arrangement of commercial-type Si cantilevers (tetrahedral Si tips), onto which single CNFs are grown, was optimized to contain 288 cantilevers in a 4 in. wafer. The ion-induced CNFs were then batch grown in the wafer scale. Scanning electron microscope observation of 50 of 288 probes randomly selected revealed that the CNFs were linear shaped, ∼400 nm in average length and ∼9 nm in average radius, and that ∼80% of the probes batch grown were suitable for practical use as qualified probes. Atomic force microscope image of a densely distributed plastic nanocolumn array obtained by the batch-grown CNF probe was clearer and less distorted, compared to that attained by a conventional Si probe. Thus, the ion-irradiation method opened up new route for the wafer-scale production of CNF probes for practical daily use. [ABSTRACT FROM AUTHOR]

Small-scale batch fabrication of Co-included carbon nanofibers (Co-CNFs) onto commercially available Si cantilevers for scanning probe microscope by an Ar+-ion-irradiation method with a simultaneous Co supply was demonstrated (eight chips/batch). As confirmed by scanning and transmission electron microscopes equipped with energy dispersive x-ray spectroscopy, Co-CNFs were fibrous and contained Co and C. With increasing the Co supply rate, Co-CNFs decreased in length from ∼600 to ∼400 nm, whereas their diameter was almost independent of the Co supply rate, 20–30 nm. As proven by magnetic force microscope (MFM) measurements using the Co-CNF probes, they were applicable as MFM probes. Since various metals including alloys can be incorporated into CNFs, this ion-irradiation method with a simultaneous metal supply was believed to be quite promising for the functionalization of CNF probes for a variety of applications. [ABSTRACT FROM AUTHOR]

Glassy carbon was Ar+-ion bombarded with a simultaneous Mo supply under ultrahigh vacuum conditions using a microprotrusion fabrication system that consists of a differentially pumped ion gun and a seed-material supply source. Conical protrusions were formed by sputtering with a seed supply, and carbon nanofibers (CNFs) grew on the tips even at room temperature. The length of CNFs reached up to ∼10 µm, and their diameter was almost uniform (50 nm) in the growth direction. The short CNFs aligned in the ion beam direction, whereas the long ones were non-aligned. The CNF growth on a glassy carbon surface was ascribed to the enhanced surface texturing and to the massive redeposition of C atoms onto cones, both of which are specific to the oblique ion bombardment: The former would lead to an increase in the number of possible nucleation sites for the CNF growth, and the C atoms arising from the latter process would migrate toward the conical tips, thus forming CNFs. [ABSTRACT FROM AUTHOR]

Anisotropic etching of hexagonal boron nitride (h-BN) and boron–carbon–nitrogen (BCN) basal plane can be an exciting platform to develop well-defined structures with interesting properties. Here, we developed an etching process of atomically thin h-BN and BCN layers to fabricate nanoribbons (NRs) and other distinct structures by annealing in H 2 and Ar gas mixture. BCN and h-BN films are grown on Cu foil by chemical vapor deposition (CVD) using solid camphor and ammonia borane as carbon, nitrogen and boron source, respectively. Formation of micron size well-defined etched holes and NRs are obtained in both h-BN and BCN layers by the post growth annealing process. The etching process of h-BN and BCN basal plane to fabricate NRs and other structures with pronounced edges can open up new possibilities in 2D hybrid materials. [ABSTRACT FROM AUTHOR]

Abstract: ZnO nanoparticles have been incorporated inside the pore system of mesoporous carbon (MC) which has been synthesized by polymerization of resorcinol and formaldehyde via soft templating approach. 5–20% of ZnO, with an interval of 5, have been incorporated almost exclusively within the mesopores by simple wet impregnation, drying and calcination procedures. The pristine MC shows high surface area (600m2/g) with large pore diameter around 7nm. After impregnation of ZnO in mesopores, the pore diameter has been decreased from 7 to 6.24nm which may relate to shrinkage of the framework or deposition of ZnO particles on the inner wall of the pores. With the increase in the ZnO percentage, the specific surface area and pore volume decreased linearly confirming the incorporation of nanoparticles inside the mesopores. TGA confirms ZnO confined in the pores of MC which also prevents the collapsing of mesoporous carbon framework upto 325°C. Interestingly, the graphitic nature of MC remains same even after impregnation of ZnO nanoparticles inside the pores. However, we strongly believe that this novel composite of ZnO and MC may play significant role in the application like oxygen reduction reactions, photocatalysis, photovoltaics, optoelectronics, catalysis and many more. [Copyright &y& Elsevier]

Abstract: Carbon nanofibers (CNFs) with a diameter of 17nm, and carbon nanoneedles (CNNs) with sharp tips have been synthesized on graphite substrates by ion irradiation of argon ions with the Co supplies rate of 1 and 3.4nm/min, respectively. Energy dispersive X-ray spectrometry, combined with selected area electron diffraction patterns has been used to identify the chemical composition and crystallinity of these carbon nanostructures. The CNFs were found to be amorphous in nature, while the structures of the CNNs consisted of cubic CoC x , orthorhombic Co2C and Co3C depending on the cobalt content in the CNNs. The diameter of the carbide crystals was almost as large as the diameter of the CNN. Compared to the ion-induced nickel carbides and iron carbides, the formation of single-crystalline cobalt carbides might be due to the high temperature produced by the irradiation. [ABSTRACT FROM AUTHOR]

Abstract: Aligned Fe-carbon composite nonofibers (Fe-CNFs) grew on graphite substrates bombarded by Ar+ ions at an oblique incident angle with a simultaneous Fe supply at room temperature. Morphology alteration and crystallinity variation of Fe-CNFs were achieved by adjusting the supply rate of Fe atoms. The effects of different Fe concentrations on the morphological and crystalline structures of Fe-CNFs were discussed in detail. The higher the Fe supply rates, the higher the Fe concentration in Fe-CNFs. Higher Fe concentration in Fe-CNFs favors the graphitization of carbon materials, but destroys the directivity of Fe-CNFs pointing to ion beam incident direction. The magnetic properties of Fe-CNFs with different Fe contents were also analyzed in detail. [Copyright &y& Elsevier]

Abstract: Various functional metal-oxide coatings on glass substrate have the possibility to be used for many applications in these days. For keeping the high performance of these applications, it is very important to understand the adsorption property on those coating surfaces. However, there are few reports about such properties of metal-oxide film surface in vacuum state, especially the carbon adsorption property on fluorine-doped tin oxide (SnO2:F) film in vacuum. In this study, we have investigated the chemical state on SnO2:F film in vacuum with XPS analysis. From the results of the SnO2:F film surface analysis, the adsorbed carbon (C1s orbit) on the SnO2:F film surface and the adsorbed carbon dependence of heat treatment in vacuum were observed. Also, it was found that the adsorbed carbon distribution on the SnO2:F film existed after the heat treatment at low temperature in vacuum, uniformly spread in large area with UV light irradiation. Besides, the influence of UV light irradiation with respect to the carbon contents in the SnO2:F film was observed by SIMS analysis. As the result, it was implied that the carbon state in the SnO2:F film remained unchanged under UV light irradiation and the carbon adsorption and desorption occurred only on the surface of the SnO2:F film. [Copyright &y& Elsevier]

Chemical Vapor Deposition (CVD) has been hugely favored when producing high-quality carbon nanomaterials and repeatable output. Despite being hugely favored, CVD typically requires a high temperature of above 1000 °C, which becomes the downside of this method. It requires a high cost and complicated processing environment, which explains the urgent need for low-temperature processing. Molecule properties of hydrocarbon precursors are believed to have played an essential role in CVD synthesis as it can affect the growth temperature, yield, crystallinity properties and indirectly affect the morphology of the carbon nanomaterials. In this review, various solid, liquid, and gaseous hydrocarbon precursors and how they affect the growth temperature of carbon nanomaterials syntheses via CVD are discussed. [Display omitted] • A variety of hydrocarbon precursors in their initial state for graphene and CNTs' growth via the CVD method is reviewed. • The mechanism involves in the formation of graphene and CNTs via the CVD method are discussed. • The binding energy of precursors and how they affect the growth temperature are discussed. • Graphene growth mechanism through active carbon atoms and carbon rings is proposed. [ABSTRACT FROM AUTHOR]