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The preparation of continous three-dimensional carbon foam composed of a few-layer graphene film decorated with carbon nanowalls standing perpendicular to its surface is presented. The synthesis is done by the direct-current PECVD method using nickel foam as a catalyst substrate. Variable curvature of the surface of the Ni foam causes a variation in electric field during the dcPECVD synthesis, which results in forming the foam of hybrid carbon structures. The material was characterized by scanning electron microscope images and by Raman spectra. The effect of plasma penetration depth on growth of carbon nanowalls is also discussed. Macropores and nanopores coexisting in the structure might offer new functionalities particularly for charge storage applications.

Carbon nanowalls (CNWs) were grown by atmospheric dc plasma enhanced chemical vapour deposition method. Maintaining plasma at atmospheric pressure give us possibility to synthetize CNWs at high rate. By using two different liquid carbon sources we can control CNWs density. Growth of sparsely distributed CNWs can be achieved by using ethanol, while hexane gives densely packed CNWs films.

Thermal expansion exhibits considerable challenges developing residual stresses at the interfaces of different materials treated at high temperature. Electrical devices containing materials with different thermal expansion behaviour very often suffer this problem. Thermal expansion co-efficient (TEC) of different metals can be tuned by using carbon nanotube (CNT). Metal matrix composites (MMCs) using CNT are fabricated by hot-press sintering method and TEC of the composites are investigated throughout a wide range of temperature (-155 to 275 °C). Reduction of TEC of the composite materials was observed up to 20% compared to that of pure metals. The effect of CNTs in the matrix materials and the mechanism behind the improvement are explained from the microscopic investigation of the composites.

Molecular nanostructures are excellent systems to study surface enhanced Raman scattering (SERS), since monolayers or sub-monolayers are expected to provide maximum scattering enhancement. The SERS enhancement is due to a plasma induced field enhancement by metallic nanoparticles. By this effect the Raman response of molecules in the immediate neighborhood of the particles can be dramatically increased. We investigated the SERS effect of Ag colloids on glass substrates and on lithographically produced nanostructures of gold and aluminum on silicon and ITO-glass. For testing extremely thin layers (monolayers and submonolayers) of 4-octyl-4'-cyanobiphenyl (liquid crystal 8CB) were prepared. The observed enhancement for 8CB on Ag colloids was about 103. Enhancement factors for the lithographic structures were initially below 100. To increase the enhancement the An nanostructures were coated with a 20 nm thick Ag-layer. Optimisation of the Ag nanoparticle geometry was investigated as an alternative SERS improvement routine. The viability of iR the chip structures for multiple usage was tested. The experimental analysis was supported by calculations of the) SERS cross-section for different structure geometries.

Hexa-perihexabenzocarbonate (HBC) are small cluster of a graphene plane with various side groups for stabilization. Due to theire ate geometry they are ideal candidates to study surface enhanced Raman spectroscopy (SERS). Very thin films HBC were vaopur deposited to different SERS-active Ag-surfaces. The enhancement of the Raman signal was studied with the goal to develop an Ag-surface of optimum enhancement, for multiple use and very simple sample preparation. For the current surface the observed enhancement is up to 10 6 . For SWNT filled with Ag-particles the SERS effect could also be shown - but enhancement was only a factor 10.

In the present work the way to grow SWCNTs, large enough to accommodate C 82 fullerenes, using non-magnetic metal catalysts is demonstrated. The growth was carried out in a water-cooled dc arc-discharge Kratschmer generator with horizontally aligned electrodes. Different methods such as Raman and optical spectroscopy, TGA and TEM were used for characterization of the materials produced under various growth conditions. The concentration of sulphur promoter strongly influences the yield of SWNTs and affects their diameter distribution. The highest relative concentration of SWCNTs with diameters larger than 1.5 nm was found for an addition of 0.9-1.3 at% of sulphur to PtRh catalysts.

Metal-induced crystallisation with layer exchange is applied on Ni/C bilayer stacks deposited by three PVD techniques on SiO2. The layer stacks were deposited at room temperature by either ion beam sputtering, direct current magnetron sputtering or high-power impulse magnetron sputtering. The influence of the Ni morphology on the layer exchange degree αLE and the resulting graphitic ordering is studied by atomic force microscopy, Rutherford backscattering spectrometry and Raman spectroscopy. The initial RMS roughness of the Ni top layer varied with the deposition technique by a factor of 20, from 0.3 to 6.1 nm. After annealing in UHV at up to 700 °C, layer exchange was observed for all samples. Still, the layer exchange degree was affected by the roughness of the initial bilayer stack. The highest value of 96% was achieved for magnetron-sputtered samples, what is by ∼35% higher than for the initially roughest Ni surfaces. Raman spectroscopy showed the formation of graphitic carbon, characterised by a strong 2D line, for all three bilayer stacks. The degree of graphitic ordering increased with decreasing Ni surface roughness.

A pressure dependence of the optical absorption spectra of BF−4-doped polypyrrole has been observed at pressures below atmospheric pressure. The two absorption bands at photon energies of 1·2 and 3·0 eV depend on the pressure: a decrease in the high-energy absorption is accompanied by an increase in the low-energy absorption and its shift towards lower energies. The Fourier transformation infrared reflection spectra also depend on the pressure in this region of pressures. The results are interpreted as a pressure-induced conformational transition of the polypyrrole chain. © 1998 John Wiley & Sons, Ltd.