Background. To analyze the biocompatibility of vertically aligned multiwalled carbon nanotubes (MWCNT), used as nanomodification to optimize the properties of prostheses-embedded microelectrodes that induce electrical stimulation of surviving retinal cells. Methods. MWCNT were synthesized on silicon wafers. Their growth was achieved by iron particles (Fe) or mixtures of iron-platinum (Fe-Pt) and iron-titanium (Fe-Ti) acting as catalysts. Viability, growth, adhesion, and gene expression of L-929 and retinal precursor (R28) cells were analyzed after nondirect and direct contact. Results. Nondirect contact had almost no influence on cell growth, as measured in comparison to reference materials with defined levels of cytotoxicity. Both cell types exhibited good proliferation properties on each MWCNT-coated wafer. Viability ranged from 95.9 to 99.8%, in which better survival was observed for nonfunctionalized MWCNT generated with the Fe-Pt and Fe-Ti catalyst mixtures. R28 cells grown on the MWCNT-coated wafers showed a decreased gene expression associated with neural and glial properties. Expression of the cell cycle-related genes CCNC, MYC, and TP53 was slightly downregulated. Cultivation on plasma-treated MWCNT did not lead to additional changes. Conclusions. All tested MWCNT-covered slices showed good biocompatibility profiles, confirming that this nanotechnology is a promising tool to improve prostheses bearing electrodes which connect with retinal tissue.

This paper describes an experimental study of gamma radiation effects in low-density arrays of vertically aligned carbon nanotubes. These arrays are characterized by excellent anti-reflective and absorbing properties for wavelengths from UV to IR, which makes them an interesting option for stray light control in optical space applications. Gamma irradiation equivalent to an estimated surface lifetime exposition in geostationary orbit does not affect the reflectivity of the structures. First high-energy proton irradiation studies indicate that the reflectivity of the carbon nanotubes forests remains unchanged.

In the present study, aligned multiwalled carbon nanotube (MWCNT) arrays were electrodeposited with manganese oxide as electrode material for capacitor application. The electrode material was prepared in a double-stage process. The first stage, the preparation of the MWCNT array on thin nickel foils by chemical vapour deposition is well known and has already been published. This study has its focus on the second step, the electrodeposition of manganese oxide on MWCNT. Electrodeposition was performed by pulse plating of manganese oxide from a manganese acetate electrolyte. The mechanism and kinetics of this deposition process were electrochemically characterised. Additionally, the manganese oxide modified MWCNT arrays were investigated by scanning electron microscopy and Raman spectroscopy. Furthermore, the capacitor performance and the increase in the capacitance of the modified MWCNT arrays were investigated by cyclic voltammetry in a sodium sulphate electrolyte

The infiltration of dissolved dyes into vertically aligned carbon nanotube arrays (va-CNT) is reported. The ultra hydrophobic surface of the CNT forest can be wetted and hence infiltrated for an appropriate choice of solvent. The dye-infiltrated CNT array forms a well ordered bulk-heterojunction structure for organic solar cells in which the CNT can act as a large electrode or, for appropriate energy levels, as an acceptor material. Derivatives of the small molecule copper phthalocyanine or the polymer poly(3-hexylthiophene) were used as dyes. Drop coating was chosen as the infiltration technique resulting in a completely embedded CNT forest. Field emission secondary electron microscopy analysis illustrates the final layer quality. Common electrical characterization under AM1.5 illumination proves photosensitivity and implies photovoltaic behavior of the composite.

The amount of information capable of being stored on a computer chip doubles every two years as stated first by Gordon Moore in 1965. Electronics packaging technology has to adopt the resulting requirements of this tremendous development of the microelectronic industry. In view of future applications it is necessary to establish new interconnect materials for high-density electronics packaging because common materials are facing physical barriers and fail to meet the requirements of nano-scale miniaturisation. These requirements will be steady miniaturisation of the electronic devices, higher current density per device, pitches down to 20 µm and higher thermal dissipation loss. Current joining elements cannot meet these requirements. For common joining element materials there are also limitations with regard to their thermomechanical behaviour. Downscaling of traditional solder bump materials to lower pitch cannot satisfy the reliability requirement [1]. For example, lead and leadfree solders typically fail when scaled down to less than 100 micron pitch due to poor fatigue resistance. On the other hand compliant interconnections do not meet the high frequency electrical requirements. Consequently, there is a need for new joining materials in electronics packaging. Carbon nanotubes (CNTs) are promising candidates for functional layers for packaging in the nanometre scale because of their superior mechanical, thermal and electrical properties. The reproducibility and the performance of such structures for thermal and electrical transport on common packaging substrates are not sufficiently known and were investigated by our groups. Latest results concerning the preparation of CNT films and their structural and functional properties are described in the present paper.Using a "bottom up" approach the CNTs are grown with a defined wall structure on a catalyst layer by chemical vapour deposition (CVD). The catalyst layer is a nano-structured deposit on a Si wafer formed by a self assembly mechanism. The nano-scaled structuring is the most important requirement for manufacturing CNTs with defined properties. Unlike state-of-the-art methods a layer of a conducting material is deposited on the Si surface as finish. This conducting layer could be the basis for the following die bonding process transferring the CNT layer on common packaging substrates. The application potential is exemplarily shown.