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Osteoblast reactions to topographic structures of titanium play a key role in host tissue responses and the final osseointegration. Since it is difficult to fabricate micro- and nano-scale structures on titanium surfaces, little is known about the mechanism whereby the topography of titanium surfaces exerts its effects on cell behavior at the cellular level. In the present study, the titanium surface was structured in micron- and submicron-scale ranges by anodic oxidation in either 0.2 M H3PO4 or 0.03 M calcium glycerophosphate with 0.15 calcium acetate. The average dimensions of pores in the structured surface were about 0.5 and 2 µm in diameter, with roughness averaging at 0.2 and 0.4 µm, respectively. Enhanced attachment of cells (SaOS-2) was shown on micron- and submicron-scale structures. Initial cell reactions to different titanium surfaces, e.g. the development of the actin-containing structures, are determined by the different morphology of the surfaces. It is demonstrated that on either micron- or submicron-structured surfaces, many well-developed filopodia were observed to be primary adhesion structures in cell-substrate interactions, and some of them entered pores using their distinct tips or points along their length for initial attachment. Therefore, porous structures at either micro- or submicrometre scale supply positive guidance cues for anchorage-dependent cells to attach, leading to enhanced cell attachment. In contrast, the cells attached to a smooth titanium surface by focal contacts around their periphery as predominant adhesion structures, since repulsive signals from the environment led to retraction of the filopodia back to the cell bodies. These cells showed well-organized stress fibres, which exert tension across the cell body, resulting in flattened cells.

Die Antennenwirkung von metallischen oder halbleitenden Nanostrukturen in elektromagnetischen Feldern soll eingesetzt werden, um chemische Reaktionen an deren Oberflächen zu optimieren. Das Ziel ist die spezifische Synthese von Oligonukleinsäuresequenzen zum Aufbau von hochdichten “DNA-Arrays” mit nanotechnologischen Methoden. Die Nanostrukturen werden für die Untersuchungen von einerseits Photonen-Transfer-Reaktionen und andererseits für Elektronen-Transfer-Reaktionen durch die Wahl geeigneter Geometrien und Materialien angepasst.

Several lower rim derivatives of calix[4]arene are compared as high resolution negative tone resists for electron beam lithography (EBL). The sensitivity of these derivatives is discussed in this paper. The suitability of calix[4]arene derivatives as top layers in bilayer resist systems is evaluated in studies on the etching resistance in an oxygen plasma. It is demonstrated that etching resistance can be improved by silylation of the resist molecules. The use of tetra(trimethylsilyloxy)calix[4]arene is compared to a common silylation step of an exposed tetraallylcalix[4]arene resist.

A new method to pattern a conductive trace on an insulating surface is investigated. A scanning force microscope (SFM) in non-contact mode is used for a single-step additive process. Vapors of an organometallic precursor are adsorbed to the surface of a substrate with pre-patterned conducting regions. A bias voltage is applied between the conducting cantilever/tip and the pre-patterned electrodes of the sample, resulting in the formation of conductive deposits at the tip location. Starting from the electrodes, the tip is moved across the insulating region where adsorbed organometallic molecules are decomposed to form conductive deposits. In this way a conducting bridge shall be formed between the pre-patterned electrodes and other structures of interest e.g. carbon nanotubes. This procedure is performed at room temperature in air with a reservoir of organometallic material close-by. The precursor, dimethylgold(III)-trifluoro-acetylacetonate sublimates at room temperature and normal pressure.

Cells are capable of reacting to a variety of differently patterned substrates. A number of hypotheses have already emerged to explain cell orientation and directed migration. It seems likely that no single hypothesis is able to explain in detail the behavior of cells that produce contact guidance. Understanding the mechanisms that influence the behavior of cells on microstructured surfaces could help to optimize the surface of future implants. A processing scheme has been developed for fabricating accurately structured Araldite replicas with titanium coating serving as implant imitates suitable for cross-sectioning. Using electron microscopy and immunogold labeling it could be shown that focal contacts of human gingival fibroblasts are formed at the walls and even at the bottom of grooves as narrow as 2 µm and as deep as 2.5 µm.

X-ray microscopy enables high-resolution analysis of thick specimens such as several microns in aqueous and atmospheric pressure environments in fields of biological and material sciences. Most commonly, zone plates (ZPs) are used as optical elements in combination with the use of synchrotron radiation (SR) as an x-ray source. It is realized at the x-ray microscopy station at BL-12 of Ritsumeikan SR center. The highest spatial resolution is 45 nm. This X ray microscope has been applied in biology, medicine, and material science. Various specimens can be clearly observed. We report some applied researches of our X-ray microscope.

Surface topography is one of the key parameters influencing cellular reactions towards artificial materials. Surfaces with defined microstructures may be useful for enhancement of the stable anchorage of transcutaneous implants in connective tissue or for prevention of epithelial downgrowth and subsequent exfoliation. Cell reactions of keratinocytes and fibroblasts were investigated on microstructured titanium experimental surfaces with alternating grooves and ridges in the range between 1–20 μm width and 0.4–2.0 μm depth. While fibroblasts displayed oriented cell growth on the structured surfaces, human keratinocytes failed to show orientation or enhanced number of focal contacts on structures in the 2–10 μm width range. In that respect, an influence of surface structure on initial cell adhesion could not be proven. The influence of a “bioactive” fibronectin (Fn) coating on adhesion and spreading of fibroblasts was tested on smooth and structured titanium model implant surfaces. Cell spreading was enhanced significantly by the fibronectin coating. Under mechanical shear stress conditions which simulated stresses during insertion of dental implants, the stimulating effects of Fn were lost on smooth surfaces due to abrasion of the coating, while complete abrasion was prevented by microstructured surfaces. The combination of microstructures with “bioactive” coatings may be used to trigger specific cell responses in areas of the implant surface with different functionality. Adhesion and growth of different cell types on microstructured surfaces was investigated by a modified technique at the electron microscopy (EM) level. The approach allows the detection of adhesion molecules in the different membrane domains by immunocytochemical gold labelling techniques. Preliminary results with this new technique suggest that vinculin is localized in the grooves rather than on the ridges in our model system.

Arrays of microelectrodes with high charge transfer capacity have been fabricated and characterized. Nano-porous titanium nitride thin films were deposited onto a 3-dimensional micro-fabricated structure etched into a biocompatible polyimide insulation layer. The polymer layer was micro-patterned by electron beam lithography and etched in an oxygen-plasma. Measurements at 1 kHz/100 mV in electrolytic solution (PBS) show a significant reduction of impedance by a factor of 0.3 to 0.2 and are in good agreement with the surface gain expected from the 3-dimensional micro-pattern. The influence of the series resistance of the buffer solution on the electrode impedance is also examined by impedance spectroscopy and finite element simulation. This kind of microelectrodes may finally be used for stimulation and recording of cells and tissue.

We have fabricated micromechanical single crystal silicon bridges for mass sensor application using silicon-on-insulator (SOI) substrate. Bridge structures, i.e. both-ends-supported beams, have a 6.3-times higher fundamental resonance frequency compared to one-end-supported cantilevers and, thus, have a higher mass sensitivity. The resonators are driven electrostatically and read out optically by means of the laser beam deflection method. Measurements of the resonator oscillation are in good agreement with the calculated fundamental resonance frequency of 262 kHz in the case shown; however, further improvements for a higher quality factor are required.

To investigate the forces acting between Staphylococcus aureus and its surrounding environment we have designed and fabricated a poly(dimethyl)siloxane substrate with microstructured pillars. The deflection of those pillars due to the adhesion of S. aureus serves as a means for force estimation and is measured in a scanning electron microscope after fixation of the incubated substrates. Our results suggest that the forces exerted by S.aureus, as a member of the class of prokaryotic cells, are higher than those typically observed for eukaryotic cells.

Over the last decades, different concepts have been established for the use of plasmonic nanostructures in sensing applications. One challenge in this context lies in delivering the analyte of interest to the location of the nanostructures and selectively attaching it to their surfaces. Here we present a method for the collection and concentration of molecules on arrays of metallic nanocones, making use of the high electric field gradients at the nanotips. For this purpose, the nanocones are integrated into a microfluidic channel and used as nanoelectrodes. By applying an AC voltage, dielectrophoresis is used to capture molecules from the channel region near the nanocones. Simulations of the dielectrophoretic forces in the channel are presented as well as experimental proof of the proposed method. After attachment of the molecules, optical read-out techniques can directly be performed on the plasmonic nanostructures.

A stable nonlinear optical point light source is investigated, based on field enhancement at individual, pointed gold nanocones with sub-wavelength dimensions. Exciting these cones with near-infrared, focused radially polarized femtosecond beams allows for tip-emission at the second harmonic wavelength (second harmonic generation, SHG) in the visible range. In fact, gold nanocones with ultra-sharp tips possess interesting nonlinear optical (NLO) properties for SHG and two-photon photoluminescence (TPPL) emission, due to the enhanced electric field confinement at the tip apex combined with centrosymmetry breaking. Using two complementary optical setups for bottom or top illumination a sharp tip SHG emission is discriminated from the broad TPPL background continuum. Moreover, comparing the experiments with theoretical calculations manifests that these NLO signatures originate either from the tip apex or the base edge of the nanocones, clearly depending on the cone size, the surrounding medium, and illumination conditions. Finally, it is demonstrated that the tip-emitted signal vanishes when switching from radial to azimuthal polarization.

Carbon nanotubes (CNTs) are ideal candidates as electrode materials for neuronal stimulation and monitoring devices such as microelectrode arrays (MEA). They provide a high charge injection limit without significant Faradic reactions and carbon nanotube electrodes have a high surface area to volume ratio. Flexible MEAs typically consist of thin conductors buried in a flexible insulator such as polyimide, where the actual contact areas have been opened by dry etching of the polyimide. CNTs are positioned in these contact areas by a low temperature (350 ° C) chemical vapour deposition process from a catalyst which was deposited on the contact in the polyimide recess. To overcome poisoning of the catalyst by outgassing from the sidewalls of the polyimide trenches even at such low temperatures, a pretreatment of the catalyst in an ammonia atmosphere for 15 min at 40 mbar and 350 °C was introduced. CNT growth on identical structures made from polyimide and silicon is compared in order to identify the relevant issues affecting growth.

Single electron devices are being investigated widely for their use in logic circuits and data storage devices. Here a point of concern is the sensitivity of single electron transistors (SETs) to changing background charges, which may arise from freezing out or capture of single electrons in the vicinity of the devices in the substrate or the buried oxide of the silicon-on-insulator (SOI) material. SET structures have been fabricated on a SOI basis and the effect of charges placed close to the quantum dot was investigated. This was performed in a low temperature scanning electron microscope (LTSEM), where a SET at liquid helium temperature was irradiated with electrons. Characterization of the SETs in the LTSEM showed the appearance of ‘random telegraph noise’.

An array of light-addressable sub-μm electrodes for contacting excitable cells is fabricated. These electrodes provide a free selectable cell–electrode contact with a high signal-to-noise ratio and high spatial resolution. A great number of lateral isolated sub-μm electrodes is placed on top of a photoconductor layer: hydrogenated amorphous silicon (a-Si:H). By use of a laser beam these sub-μm electrodes located under the cell can be selected forming an electrical contact via an indium tin oxide (ITO) lead to an amplifier, thus providing a high seal resistance at the cell–electrodes interface. The feasibility of light-addressing electrodes and fabrication of sub-μm electrodes on photoconductor layer is shown.

We have defined Coulomb blockade structures in a highly doped poly-crystalline film on top of a SiO 2 layer using electron beam lithography and thermal oxidation. The electrical characterization at 4.2 K revealed a 8 mV wide Coulomb blockade region. The Coulomb blockade can be lifted periodically by applying a voltage to the side as well as the back gate. We conclude that these effects are due to a single electrically active island, which can be directly linked to our lithographically defined structure.

Design rules for lateral pn-junction detectors have been established and verified by numerical simulations and measurements of the detector efficiency for different geometries. The test devices were fabricated by diffusion of phosphorus into boron-doped silicon substrates. The efficiency was measured by direct electron irradiation in a scanning electron microscope. EBIC imaging was used to obtain the depletion layer width used for calculating the upper limit of the efficiency for the given geometries. All experimental values agree well with the theoretical predictions. It is demonstrated that the efficiency of lateral pn-junction detectors can be improved without reduction of the bandwidth.

We present micromechanical cantilever sensor arrays for quantification of individual components in a gas mixture. Using selectively coated cantilevers as mass sensitive transducers, their response to the analyte molecules is obtained by measuring their resonant frequency shift due to the additional mass loading. The responses were used in principal component regression (partial least squares (PLS)) for the quantitative prediction of vapors being analyzed. The results confirm the functionality of our sensor system and motivate for further optimization.

A process for the fabrication of ultra-small silicon single electron transistors with 10nm constrictions and 40nm island diameters based on electron beam lithography with hydrogen silsesquioxane negative resist and reactive ion etching of a thin silicon on insulator device layer is presented. The observed Coulomb blockade at room temperature indicates that even at this size small dopant clusters are formed in highly doped material and act as effective islands in a multi-junction device.

The transport properties of two adjacent double dots, realized in silicon is studied by DC-measurements at a temperature of 4.2 K. From the measured charging diagrams the capacitances within the structure are estimated and using this information as input for a simple electrostatic model the energy scales for electron transitions between two dots are calculated. The change of energy in one pair introduced by an interdot electron transition in the other, the basic transition for the operation of quantum cellular automata, is shown to be less than the thermal energy under the present conditions. Adding an extra electron into the system causes larger energy changes in the double dots and for such transitions a clear correlation in electron transport for both double dots can be observed. The size of this effect complies with our model and the estimated capacitances and can therefore be used as a base for future cell design.

Polymer coated cantilevers as mass-sensitive transducers for miniaturized gas sensors, an approach for which promising results have been demonstrated recently [1], have been developed and investigated further towards applications. A new detection arrangement has been realized, which enables a simultaneous frequency readout of several cantilevers. In addition, it was possible to coat the cantilevers with different polymers showing specific sensitivity to different gases. Finally, we present the first measurements on the simultaneous application and readout of differently coated cantilevers exposed to a mixture of gases.

Self-assembled Monolayers of calix[4]resorcinarene receptor molecules on Au(111) were studied by UHV scanning tunneling microscopy and X-ray photoelectron spectroscopy. Highly ordered monolayers were observed with domains oriented at an angle of 60° relative to each other. Molecularly resolved images were investigated and lattice constants found which depended on the preparation solvent. The STM images of two samples, one prepared in 1 mM chloroform/ethyl alcohol adsorbate solution and one in 1 mM hexane adsorbate solution are consistent with having a \(\)×2\(\) and 4×2\(\) lattice, respectively.

We present a systematic investigation of the oxidation properties of Si dots fabricated on a silicon-on-insulator (SOI) wafer. Dots with diameters varying from 9 to 81 nm were structured on a SOI wafer. These dots were oxidized in a dry oxygen atmosphere at 700, 850, and 1000 °C. The resulting structures were investigated using a side view transmission electron microscopy (TEM) technique in combination with energy filtered TEM. The dimensions of the residual Si and the grown SiO2 were then extracted from the micrographs and analyzed. The oxidation appears to be retarded as compared to the well-known planar oxidation. At 700 and 850 °C a self-limiting effect is observed as well as a clear pattern dependent oxidation at 850 and 1000 °C. We attribute these effects to stress buildup in the oxide. The critical stress, causing the self-limiting effect, is calculated using a model that considers the decrease of the reaction rate with increasing stress perpendicular to the Si surface.

Superconducting thin Nb films are deposited on top of a regular array of vertical carbon nanotubes, grown by plasma enhanced vapor deposition. The carbon nanotubes are expected to serve as columnar pinning sites for vortices in the (mixed-state) superconductor. Electric transport measurements reveal a suppression of vortex flow as well as an enhancement of the critical depinning current due to the presence of carbon nanotubes.

Under excitation with an external electromagnetic field, gold nanocones act as efficient optical antennas. In this work, a process developed for the fabrication of sharp-tipped gold nanocones on silicon is extended to transparent substrates covered by a thin conducting layer. In this configuration, the cones can be investigated in scanning probe microscopes while illuminating from below. The electric coupling between cones and substrate and between individual cones can be varied by a precise thinning of the conducting layer via a fine-tuning of the original layer thicknesses.

We have fabricated and characterized a uniformly n-doped silicon double-dot structure. The electrical behaviour could be changed between that of a multiple tunnel junction and that of a double dot by applying appropriate gate voltages. The double-dot characteristics observed can be attributed to the geometry of the structure, and it is shown that the influence of the multiple tunnel junctions can be entirely eliminated. In the double-dot regime, characteristic charging diagrams were obtained by independently sweeping two sidegate voltages. Using a classical capacitance equivalent circuit the hexagonal lattice of the conductance resonances in the charging diagram was modelled and single-electron charging in the geometrical double dot is concluded from the match between model and experimental data.

Changes in the resonance frequency of polymer-coated cantilevers due to gas absorption is shown to be a promising detection mechanism for gases. We prepared SiN x cantilevers based on micromachined Si wafers and used polydimethylsiloxane (PDMS) as polymeric prototype coating. We measured the resonance frequency response of cantilevers end-coated with polymer on exposure to different vapor concentrations of n -octane, toluene, and n -butanole and determined high sensitivities with respect to cantilevers without polymer coating. By using the first higher resonance mode, we found with our configuration sensitivities up to −0.0988 Hz/ppm for small concentrations of n -octane. It is demonstrated here how the sensitivity of the chemical sensor can be improved by varying the deposited polymer mass.

We have fabricated SiN"x cantilevers which can be used for applications as miniaturized gas sensors. Cantilevers were coated with polydimethylsiloxane as a chemically sensitive layer and the additional mass loading by the absorption of gas molecules was detected by measuring the change of the resonance frequency of the structures. For the detection of n-octane a sensitivity of -0.099 Hz/ppm is obtained. This value is comparable to the sensitivity of conventional quartz crystal microbalances. The simultaneous detection of the resonance frequencies of different cantilevers for analyzing a gas mixture is demonstrated.

Silicon Coulomb blockade structures have been fabricated from silicon on insulator substrates and electrically characterised. The devices were realized as a single Si island connected to two electron reservoirs by Si tunnelling barriers. The silicon base substrate served as a backgate. Clear Coulomb blockade behaviour in the I(V) characteristics was observed at temperatures up to 110K with a large Coulomb gap of 1 Volt at zero backgate voltage. The Coulomb gap was found to be strongly dependent on the backgate voltage. Periodic source-drain current oscillations were measured at 4.2K by sweeping the backgate voltage. The geometrical and the electrical shape of the device were found to be different. Despite the designed two tunnelling barriers and a single dot the observed electrical behaviour can only be explained by the assumption of multiple tunnel junctions.

Shubnikov–de Haas (SdH) and Hall measurements have been used to investigate a pair of adjacent two-dimensional electron gases (2DEGs) which were formed in two n 0.53 Ga 0.47 As quantum-wells, separated by a thin In 0.52 Al 0.48 As barrier, grown lattice-matched on InP. This double quantum-well system consists of two asymmetric InGaAs quantum wells, 9 nm and 7 nm respectively, separated by a 4.5 nm InAlAs barrier. The existence of two occupied electronic subbands with differing electron densities can clearly be identified by beating effects in the SdH oscillations. By applying a substrate bias the electron densities can be tuned and the beating is shifted. In the simultaneously performed Hall measurements additional features can be observed: Hall measurements with different total electron densities reveal plateaus for integer filling factors ν (with ν = ν 1 + ν 2 , ν 1 and ν 2 both integers, corresponding to the two subbands). Some even filling factors become suppressed and recover with changing electron density. Also, for some densities an odd filling factor is observed. The systematic tuning of the electron densities via the application of a bias voltage to the front gate reveals two Landau fans, one for each electronic system, respectively, crossing each other. The electron densities for both electronic systems can be identified by analysing the SdH spectra. As a function of the front-gate voltage, these densities seem to show evidence for an anticrossing of the two electronic states and therefore for a strong coupling between the states.

We report an inexpensive and simple way of performing nanoimprint-lithography. For this purpose a stamp is fabricated by using electron beam patterning of hydrogen silsesquioxane (HSQ) on a silicon substrate. The developed HSQ-resist can be used directly as a stamp for nanoimprint-lithography. Thus with a simple imprinting setup and an improved stamp fabrication process high resolution imprints can easily be made. The method reported here differs from previous work in the specific method of baking and developing the HSQ-resist and the imprint process. Reproducible imprints can be obtained by pressing the stamp in a layer of heated PMMA spin-coated on a silicon substrate.

We present a systematic study on properties of calix[n]arenes as a high resolution negative tone electron beam resist. From experiments changing the ring sizes of the calix[n]arenes with n=4,6,8 as well as the functionalisation of the arenes we conclude that electron beam irradiation causes the arenes to break up and link to other arenes or functionalizing groups. This is confirmed by exposing resorcin[4]arene. We demonstrate that this material also shows negative tone high resolution resist features, and patterns are transferred into silicon.

We have fabricated an array of electrostatic octupoles consisting of silicon electrodes on borosilicate glass as carrier material and isolator. Metal wires on the glass carrier connect the electrodes with contact pads on outer areas. This enables the fabrication of hundreds of multipoles with the possibility of external control. Measurements with regard to electrical resistance and estimates of critical frequencies are presented.

Titanium is the material of choice for many medical implants. The cells being directly in touch with the implant surface should not only survive but develop a strong adhesion to this surface. The topographic structure of biomaterial surfaces has a strong influence on cellular reactions. Therefore the study of the interface between cell monolayers and Titanium surfaces is of high interest. Relevant techniques in this field are transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The major challenge for the preparation is the cross-sectional cutting of the samples which is required for TEM analyses. For conventional ultrathin sectioning using an ultramicrotome, the preparation of the cell-substrate interface is rather complicated, e.g., involving Titanium coated Araldite replica of structured surfaces [D.L. Cochran, J. Simpson, H.P. Weber, D. Buser, Int. J. Oral Maxillofac. Implants 9 (1994) 289-297]. In this study, nanostructured surfaces were fabricated by electron beam lithography process (ebeam) where the negative resist hydrogen silsesquioxane (HSQ) was directly sputter coated with Titanium. Focused ion beam (FIB) was used for the cross-sectioning for SEM and TEM analyses.

We have fabricated arrays of silicon membranes and structures such as silicon contact pads and interconnecting silicon-wires on borosilicate glass as carrier material and isolator. We propose a new method to align and assemble these basic modules to form electrostatic electron optical components such as lenses and multipoles. This enables the fabrication of arrays of mutually aligned e-beam microcolumns.

We have designed a new Digital Pattern Generator for electron beam lithography applications which is able to generate polynomially bordered shape primitives by hard wired logic. This Pattern Generator has been built and the basic functions have been tested. In connection with an offline spline interpolation program, this device allows the fast generation of deflection signals for structures with arbitrarily curved borders.

The scanning tunneling microscope (STM) was utilized to generate nanoscale features on epitaxially grown, c-axis oriented YBa2Cu3O7-δ (YBCO) films. To gain a deeper understanding of the process responsible for the nanometer-sized modifications, the experiments were performed under ambient conditions as well as in ultra high vacuum (UHV). In air, systematic modifications on the scale of a few YBCO unit-cells could be achieved by applying different techniques. However, the fabrication of structures of similar size failed under vacuum conditions. This suggests that water vapor plays an important role in the generation of nanometer-sized features. Therefore, we conclude that in air an electron-induced chemical decomposition lowers the barrier height for field-evaporation and thus allows a more confined removal of material with a lower electric field.

Metallic nanocones are well-suited optical antennas for near-field microscopy and spectroscopy, exhibiting a number of different plasmonic modes. A major challenge in using nanocones for many applications is maximizing the signal at the tip while minimizing the background from the base. It is shown that nanocone plasmon resonance properties can be shifted over a wide range of wavelengths by variation of the substrate, material, size and shape, enabling potential control over specific modes and field distributions. The individual resonances are identified and studied by correlated single particle dark field scattering and scanning electron microscopy in combination with numerical simulations.

A fully parallel approach for the fabrication of arrays of metallic nanocones and triangular nanopyramids is presented. Different processes utilizing nanosphere lithography for the creation of etch masks are developed. Monolayers of spheres are reduced in size and directly used as masks, or mono- and double layers are employed as templates for the deposition of aluminum oxide masks. The masks are transferred into an underlying gold or silver layer by argon ion milling, which leads to nanocones or nanopyramids with very sharp tips. Near the tips the enhancement of an external electromagnetic field is particularly strong. This fact is confirmed by numerical simulations and by luminescence imaging in a confocal microscope. Such localized strong fields can amongst others be utilized for high-resolution, high-sensitivity spectroscopy and sensing of molecules near the tip. Arrays of such plasmonic nanostructures thus constitute controllable platforms for surface-enhanced Raman spectroscopy. A thin film of pentacene molecules is evaporated onto both nanocone and nanopyramid substrates, and the observed Raman enhancement is evaluated.

A soft X-ray microscope with zone plates was set up at UVSOR [synchrotron radiation facility (750MeV, 200mA) at Institute for Molecular Science, Okazaki, Japan]. A 50nm line & space pattern could be resolved at λ=3.2nm. With an environmental chamber (wet cell) using SiN windows, wet biological specimens, such as letus protoplasts, rabbit myofibrils, tubulin of COS cell and Deinococcus radiodurans strains, could be observed at λ=2.5nm. In the present microscope, the numerical aperture of the condenser was much smaller than that of the objective. To adjust both the numerical apertures, an ellipsoidal condenser mirror system was tested, and preliminary result (an image of Cu mesh, 12.7μm pitch) was obtained.

We have developed metal-semiconductor-metal structures for low energy electron detection. Devices, with 250 nm wide Ti-fingers and 1.3 μm spacing, were fabricated using e-beam lithography on high resistivity Si. An amplification of incident low energy electrons of up to 200 is demonstrated. This feature together with the planar geometry of the device should allow application in 1 kV microcolumns.

Carbon nanotubes (CNTs) are ideal candidates as electrode materials for neuronal stimulation and monitoring devices, since they provide a high charge injection limit without significant Faradic reactions, and carbon nanotube electrodes have a high surface to volume ratio. CNTs are positioned at desired locations by chemical vapour deposition (CVD) growth from patterned catalysts. However, these processes typically require temperatures above 700 °C, which is unacceptable for many flexible substrate materials like polyimide, which looses its insulating properties around 400 °C and its stability at 600 °C. By proper selection of parameters such as catalyst material, gas composition, processing pressure and time, it is possible to grow CNTs at temperatures as low as 350 °C with a total CNT height of ∼1 µm on silicon. On polyimide additional substrate and catalyst pretreatment is necessary at such low temperatures. This indicates that the substrate may influence the growth process of CNTs.

Dispersion forces are long-range interactions between polarizable objects that arise from fluctuations in the electromagnetic field between them. Dispersion forces have been observed between microscopic objects such as atoms and molecules (the van der Waals interaction), between macroscopic objects (the Casimir interaction) and between an atom and a macroscopic object (the Casimir-Polder interaction). Dispersion forces are known to increase the attractive forces between the components in nanomechanical devices, to influence adsorption rates onto nanostructures, and to influence the interactions between biomolecules in biological systems. In recent years, there has been growing interest in studying dispersion forces in nanoscale systems and in exploring the interactions between carbon nanotubes and cold atoms. However, there are considerable difficulties in developing dispersion force theories for general, finite geometries such as nanostructures. Thus, there is a need for new experimental methods that are able to go beyond measurements of planar surfaces and nanoscale gratings and make measurements on isolated nanostructures. Here, we measure the dispersion force between a rubidium atom and a multiwalled carbon nanotube by inserting the nanotube into a cloud of ultracold rubidium atoms and monitoring the loss of atoms from the cloud as a function of time. We perform these experiments with both thermal clouds of ultracold atoms and with Bose-Einstein condensates. The results obtained with this approach will aid the development of theories describing quantum fields near nanostructures, and hybrid cold-atom/solid-state devices may also prove useful for applications in quantum sensing and quantum information.

Low temperature electron transport measurements of single electron transistors fabricated in advanced CMOS technology with polysilicon gates not only exhibit clear Coulomb blockade behavior but also show a large number of additional conductance fluctuations in the nonlinear regime. By comparison with simulations these features are quantitatively attributed to the effects of discretely charged islands in the polysilicon gates.

We report electronic transport on n-type silicon Single Electron Transistors (SETs) fabricated in Complementary Metal Oxide Semiconductor (CMOS) technology. The n-MOSSETs are built within a pre-industrial Fully Depleted Silicon On Insulator (FDSOI) technology with a silicon thickness down to 10 nm on 200 mm wafers. The nominal channel size of 20 $\times$ 20 nm$^{2}$ is obtained by employing electron beam lithography for active and gate levels patterning. The Coulomb blockade stability diagram is precisely resolved at 4.2 K and it exhibits large addition energies of tens of meV. The confinement of the electrons in the quantum dot has been modeled by using a Current Spin Density Functional Theory (CS-DFT) method. CMOS technology enables massive production of SETs for ultimate nanoelectronics and quantum variables based devices., Comment: 4 Figures

A novel spectrometer is employed to study the spectrum of heavily doped quantum dots. A single-particle discrete spectrum is found to exist only in close vicinity to the Fermi energy. Levels further away are broadened beyond the average level spacing and merge to form a quasi-continuous spectrum. The broadening is traced to electron-electron interaction in the dot. For the discrete part of the spectrum, level statistics is studied as a function of magnetic field and found to agree remarkably well with recent calculations.

Scanning probe microscopes are widely used to study surfaces with atomic resolution in many areas of nanoscience. Ultracold atomic gases trapped in electromagnetic potentials can be used to study electromagnetic interactions between the atoms and nearby surfaces in chip-based systems. Here we demonstrate a new type of scanning probe microscope that combines these two areas of research by using an ultracold gas as the tip in a scanning probe microscope. This cold-atom scanning probe microscope offers a large scanning volume, an ultrasoft tip of well-defined shape and high purity, and sensitivity to electromagnetic forces (including dispersion forces near nanostructured surfaces). We use the cold-atom scanning probe microscope to non-destructively measure the position and height of carbon nanotube structures and individual free-standing nanotubes. Cooling the atoms in the gas to form a Bose-Einstein condensate increases the resolution of the device.

This paper discusses the development of a new approach based on scanning tunneling microscope (STM), microfabricated lenses and field emission technology to form an exceptionally high brightness electron source and miniaturized electron probe forming columns. Electron optical studies have shown that such miniaturized columns, measuring millimeters in length and diameter, can have performance surpassing conventional columns at the same potential. Processes for fabricating microlenses from silicon membrane using electron beam lithography and reactive ion etching (RIE), and a special W field emission tip preparation and annealing procedure have been developed. Prototype 1kV microcolumns based on this concept measuring 2.5 mm have been successfully fabricated and demonstrated to be fully operational. Scanning electron microscope images in the transmission mode have been achieved. The expected performance of such microcolumns coupled with the very significant reduction in physical column size can open new possibilities in many applications which include lithography, microscopy, metrology, testing, storage, etc.. It can be shown that by the use of an array of these miniaturized columns, high throughput sub-100nm lithography can be achieved.