Pulsed electron beam ablation (15 keV, 1 kA, 100 ns) has been used to grow thin films of nanocrystalline diamond on silicon substrates. The films have been grown at room temperature and 150°C, and under argon as the working background gas at a pressure of about 4 mTorr. Visible reflectance spectroscopic analysis has shown films thickness to range between about 55 nm and 115 nm. Visible-Raman spectroscopic measurements have confirmed the presence of sp3 carbon bonds with a substantial fraction in the deposited films, and surrounded by a graphitic phase. The morphological features of the films have been assessed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The films surface is relatively smooth at room temperature and for low thickness, and becomes rougher at high temperature and for thicker films.

Graphene, a monolayer of sp2-bonded carbon atoms, has been attracting worldwide interests because of its unique two-dimensional structure, various fascinating properties and a wide range of intriguing potential applications. The graphene research is very active in China and has been developing rapidly in the past few years, which covers nearly all the areas related to graphene including theories, synthesis, physical and chemical properties, and applications. Over 100 research institutions have been involved in graphene research with fast-growing project supports. In this paper, the status of graphene research in China is first discussed based on the number of publications and patents as well as the institutions involved. Then the projects and fundings from both government and companies for graphene research are briefly introduced. Finally, the highlights of graphene research in China are reviewed, which include chemical vapor deposition growth and transfer, mass production, and assembly of graphene, and its applications in energy storage, sensing, composites and solar cells.

We have developed a facile synthetic method for highly water-soluble, hollow carbon nanoparticles with a diameter of ∼1 nm, as a so-called fullerenol. The method was extended to fullerene soot to obtain the corresponding hydrophilic carbon materials, and the products were subjected to IR and elemental analysis. Particle size analysis demonstrated the relatively high dispersion of particles with diameters of ∼70 nm, in water. The surface analysis using FE-SEM showed the difference in morphology between fullerene soot and activated carbon as well as between before and after hydrophilic treatment of the soot with hydrogen peroxide. Moreover, this hydrophilic fullerene soot exhibited high antioxidant activity as compared with fullerenol and C60.

Graphene is a promising material for electronic and spintronic applications due to its high carrier mobility and low intrinsic spin-orbit interaction. However, extrinsic effects may easily dominate intrinsic scattering mechanisms. The scattering mechanisms investigated here are associated non-magnetic, charged impurities in the substrate (e.g. SiO2) beneath the graphene layer. Such impurities cause an electric field that extends through the graphene and has a non-vanishing perpendicular component. Consequently, the impurity, in addition to the conventional elastic, spin-conserving scattering can give rise to spin-flip processes. The latter is a consequence of a spatially varying Rashba spin-orbit interaction caused by the electric field of the impurity in the substrate. Scattering cross-sections are calculated and, for assumed impurity distributions, relaxation times are estimated.

Optical absorption efficiency, an important metric for sensing, radiometric and energy harvesting applications, has been studied theoretically and experimentally in porous, ordered nanostructures, including multi-walled- (MW) carbon nanotubes (CNTs) and single-walled- (SW) CNTs. We have characterized the absorption efficiencies in the 350 nm -7000 nm wavelength range of vertically aligned MWCNT arrays with high site densities synthesized directly on metallic substrates using a plasma-enhanced (PE)- chemical vapor deposition (CVD) process. Our ultra-thin absorbers exhibit a reflectance as low as ∼ 0.02 % (100 X lower than the benchmark). Such high efficiency absorbers are particularly attractive for radiometry, as well as energy harnessing applications. This work increases the portfolio of materials that can be integrated with such absorbers due to the potential for reduced synthesis temperatures arising from a plasma process. Optical modeling calculations were conducted that enabled a determination of the extinction coefficient in the films.

We present a Scanning Probe Microscopy study of doping and sensing properties of reduced graphene oxide (rGO)-based nanosensors. rGO devices are created by dielectrophoretic assembly of rGO platelets onto interdigitated electrode arrays, which are lithographically pre-patterned on top of SiO2/Si wafers. The availability of several types of oxygen functional groups allows rGO to interact with a wide range of organic dopants, including methanol, ethanol, acetone, and ammonia. We perform sensitive Scanning Kelvin Probe Microscopy (SKPM) measurements on patterned rGO electronic circuits and show that the local electrical potential and charge distribution are significantly changed when the device is exposed to organic dopants. We also demonstrate that SKPM experiments allow us to quantify the amount of charge transferred to the sensor during chemical doping, and to spatially resolve the active sites of the sensor where the doping process takes place.

We report on mid-infrared (600 – 4000 cm-1), refection-type optical-Hall effect measurements on epitaxial graphene grown on C-face silicon carbide and present Landau-level transition features detected at 1.5 K as a function of magnetic field up to 8 Tesla. The Landau-level transitions are detected in reflection configuration at oblique incidence for wavenumbers below, across and above the silicon carbide reststrahlen range. Small Landau-level transition features are enhanced across the silicon carbide reststrahlen range due to surface-guided wave coupling with the electronic Landau-level transitions in the graphene layer. We analyze the spectral and magnetic-field dependencies of the coupled resonances, and compare our findings with previously reported Landau-level transitions measured in transmission configuration [4,5,6]. Additional features resemble transitions previously assigned to bilayer inclusion [21], as well as graphite [15]. We discuss a model description to account for the electromagnetic polarizability of the graphene layers, and which is sufficient for quantitative model calculation of the optical-Hall effect data.

A modified critical point model dielectric function for graphene is derived here and used to analyze spectroscopic ellipsometry data obtained over a wide spectral range from 3 to 9 eV. Critical point and exciton resonance energies are extracted and discussed. Our findings indicate that epitaxial graphene on SiC to exhibits equivalent exciton behavior to that of suspended graphene. We further apply our model dielectric function to evaluate dielectric function data for highly oriented pyrolytic graphite reported in the literature. Excellent agreement is found between the critical point model developed here and the literature data even for the low energy spectral range up to 1 eV.

The effects of the pulsed green laser annealing at ambient nitrogen for two different heights-CNWs grown on silicon substrate were investigated on the crystallinity and morphology using Raman spectroscopy, SEM, TEM and XPS. For the 1μm height-CNWs, the peak intensity of D-band spectra decreased as the laser energy density increased up to 1.3Jcm-2, ID/IG ratio decreased from 2.5 to 0.7. The crystallinity of CNWs was improved by the laser irradiation. For the 1μm height-CNWs irradiated above 1.5Jcm-2, the height of CNWs decreased gradually as the laser energy density increased, it was clarified that the surfaces of CNWs were vaporized by the laser irradiation. For the 20μm height-CNWs, the peak intensity of D band spectra also decreased until the laser energy density increased up to 0.8Jcm-2, ID/IG ratio decreased from 1.6 to 0.5. From the TEM observation of CNWs irradiated at 0.8 Jcm-2, it was confirmed that the laser irradiation changed CNWs to be highly oriented crystal structure. However above 0.8Jcm-2, the crystallinity was deteriorated due to the vaporization of CNWs as the same as the 1μm height-CNWs. The pulsed green laser annealing is effective to improve the crystallinity of CNWs on optimal laser energy density for both height-CNWs, the higher laser energy densities vaporized the CNWs and changed the morphology and crystallinity of CNWs.

Amorphous carbon (a-C) films have a growing interest in the biological and medical field, as a coating material, due to their biocompatibility and antibacterial property. However, a-C films deposited directly on polymers often show adhesion failure.

In this paper, two types of a-C films, amorphous hydrogenated carbon (a-C:H) film and hydrogen-free a-C (H-free a-C) film were deposited on polytetrafluoroethylene (PTFE) using a plasma deposition method. Prior to a-C film coating, the PTFE substrates were treated with Ar and O2 plasma and an appropriate interlayer was chosen to enhance the adhesion strength. The effect of the plasma pretreatment on the chemical composition of the PTFE was investigated by X-ray photoelectron spectroscopy (XPS). A T-peel test was carried out to evaluate the adhesion strength of the a-C coated PTFE. In the T-peel test, Ar plasma pretreatment improved the adhesion strength more effectively than that of O2 plasma pretreatment, because of the substantial defluorination and oxygen bonding occurred by Ar plasma pretreatment. Moreover, H-free a-C film reduced the numbers of Escherichia coli (E. coli) colonies dramatically, compared with original PTFE and a-C:H coated PTFE. Consequently, H-free a-C film coating can be a promising method to inhibit the increase of bacteria.

We present our preliminary results on a novel technique to electrophoretically sort singlewall carbon nanotubes into metallic and semiconducting tubes using a free-solution nonionic surfactant in a homemade electrophoretic vertical cell. The technique is used to sort purified commercial product SWCNTs, (Thomas Swan Elicarb) into metallic and semiconducting tubes. In contrast to onventional electrophoresis techniques, which takes more than 24 hours to obtain efficient separation, our approach takes ∼ 6 hours to achieve efficient separation, which reduces the separation time by four fold. Characterization of the sorted tubes with micro-Raman spectroscopy analysis shows very strong enrichment of both metallic and semiconducting tubes.

Carbon nanofibers (CNFs) have been thoroughly investigated as potential anode materials in Li-ion battery owing to their exceptional properties such as the higher surface area to mass ratio, electrical conductivity and mechanical toughness. However, one of the major limitations of nano carbon materials is lower mass loading density. To address this issue, we have developed a novel anode system composed of CNFs directly grown on 3D Cu mesh current collector (hereafter mentioned as 3D CNFs) using a thermal catalytic chemical vapor deposition (CVD) method. Compared to CNF-based anodes on 2D Cu current collector, active The active material loading amount of the 3D CNFs has been found to be 400 % higher while comparing with 2D CNF. Owing to an increase of the active surface area, 3D CNFs demonstrated enhanced electrochemical performance of Li-ion battery in terms of charge capacity (50% improvement), rate capability and cycling life. Interfacial contact between the CNFs and Cu could play a crucial role in promoting the electrochemical properties. The intermediate TiC thin layer, formed at high temperature 750°C, could function as an efficient electric conducting pathway and a strong bonding bridge between the CNFs and Cu. In order to improve the pristine 3D CNF redox reactions, the amorphous Si (a-Si)/3D CNF has been sputter deposited to produce Si wrapped 3D CNF hybrid anode material. It has been found that the electrochemical properties of the a-Si/3D CNF yields superior specific capacity (Cdis 549 mAhg-1, LiC4.1) and cycling stability than that of pristine 3D CNF (461 mAhg-1, LiC4.8).

In this study, the failure mechanisms of graphene under sliding are examined using atomistic simulations. A 6nm diameter diamond tip is slid (at a controlled normal load) over a graphene monolayer that is adhered to a semi-infinite silicon substrate. The impact of tip adhesion on the wear and frictional behavior of graphene is studied by comparing two diamond tips, one of which has been hydrogen-passivated and the other which is bare carbon. By contrasting the passivated and unpassivated tips, the interplay of adhesive and abrasive wear on the graphene membrane can also be compared. The results of this work indicate that chemical bonding between the tip and the graphene greatly exacerbates tearing in the graphene monolayer by plowing ahead of the indenter, causing material build-up and increasing effective contact area.

Graphene possesses excellent mechanical, thermal and electronic properties, not to mention its optical transparency and chemical stability. Much effort has been made towards the control of its physical properties for technological applications. One way to achieve this control is by modifying graphene size and structure. Recently, in a search for the development of semiconducting graphene structures to be produced at large scale, a new structure called graphene nanomesh was synthesized by means of block copolymer lithography and other methods. Basically, a graphene nanomesh is a graphene structure made to possess a periodic array of nanoscale holes whose sizes and hole-to-hole (or neck) distances are considered as control parameters for its overall electronic properties. Although the electronic properties of graphene nanomeshes are being intensively studied, their mechanical properties are still to be investigated. This work, then, presents the first study of mechanical, structural and thermal properties of graphene nanomeshes as a function of hole and neck sizes, through atomistic molecular dynamics simulations. The dependence of the Young’s modulus and coefficient of thermal expansion of graphene nanomeshes on the hole and neck sizes will be shown.

Studies have demonstrated that the reinforcement of polymeric matrices using nanofiller can results with better thermo-physical properties of polymer. Carbon nanofiber (CNF) is a unique quasi-one dimensional nanostructure with large numbers of edges and defects compared to carbon nanotube (CNT). Further the availability in large quantity along with lower cost makes them an important nanomaterial for future technology. We have previously used CNF in different thermoplastic polymers. In this study CNFs were used with water soluble thermoplastic aliphatic polyster polylactic acid (PLA) and studied their thermal and mechanical properties. Thermal analysis using Thermogravimetric Analysis showed enhanced thermal stability of the polymer at higher nanotube loading (>1 wt%) and decrease of thermal stability at higher loading (>10 wt%). Crystallization thermogram of PLA was modified heavily with the addition of nanofibers changing clearly from one stage to two stage crystallization. In addition, CNF facilitates the crystallization of PLA resulting in an increase of its crystallization. The mechanical testing showed the steady increase of modulus of the composites with the nanofiber content within the range of study which can be regarded as due to the change in interface property of the composites.