Flexible fluidic microchips based on thermoformed and locally modified thin polymer films.

This paper presents a fundamentally new approach for the manufacturing and the possible applications of lab on a chip devices, mainly in the form of disposable fluidic microchips for life sciences applications. The new technology approach is based on a novel microscale thermoforming of thin polymer films as core process. The flexibility not only of the semi-finished but partly also of the finished products in the form of film chips could enable future reel to reel processes in production but also in application. The central so-called 'microthermoforming' process can be surrounded by pairs of associated pre- and postprocesses for micro- and nanopatterned surface and bulk modification or functionalisation of the formed films. This new approach of microscale thermoforming of thin polymer film substrates overlaid with a split local modification of the films is called 'SMART', which stands for 'substrate modification and replication by thermoforming'. In the process, still on the unformed, plane film, the material modifications of the preprocess define the locations where later, then on the spatially formed film, the postprocess generates the final local modifications. So, one can obtain highly resolved modification patterns also on hardly accessible side walls and even behind undercuts. As a first application of the new technology, we present a flexible chip-sized scaffold for three dimensional cell cultivation in the form of a microcontainer array. The spatially warped container walls have been provided with micropores, cell adhesion micropatterns and thin film microelectrodes.

One- and two-photon spectroscopy with rare gas solids.

Excitation energies, oscillator strengths, and line shapes for valence excitons in rare gas solids are presented and discussed in the light of recent theoretical approaches. In a second section, first results are reported for solid Kr obtained in a two-photon photoemission experiment combining synchrotron radiation and a laser.

Fine structure and temperature dependence of shallow core excitons in insulators and semiconductors.

The excitonic spectra associated with the shallow core levels K(+)3p, Ga3d, and In4d in potassium halide and III-V semiconductor single crystals were studied by high resolution reflectivity (DeltaE < 10 meV) as a function of temperature down to 20 K. Analysis of the fine structure, transition energies, line profiles, halfwidths, and their temperature dependence yields information on the exciton (electron)-phonon interaction and on the influence of lattice expansion. Strong electron-phonon coupling dominates in the K(+)3p excitons as it does in F centers, whereas weak coupling describes the core excitons in semiconductors. The contributions of initial and final states are discussed. Core surface excitons in semiconductors show a significantly smaller temperature coefficient than the volume excitons.

Deep X-ray lithography with a tunable wavelength shifter at CAMD.

An additional X-ray lithography facility is under construction at the Center for Advanced Microstructures and Devices. It will receive radiation from a 7.5 T superconducting three-pole wavelength shifter. The critical energy of the insertion device is tunable up to a maximum value of 11.2 keV, allowing for optimization of photon spectra to resist thickness. In particular, this hard X-ray source will allow investigation of X-ray lithography at very high energies for devices with thicknesses in excess of 1 mm, and study of low-cost mass-production concepts, using simultaneously exposed stacks of resist layers.

High resolution monochromator for the VUV radiation from the DORIS storage ring.

The unique properties of the DORIS storage ring at DESY as a synchrotron radiation source are exploited for high resolution spectroscopy in the vacuum ultraviolet. We describe a new experimental set up with a 3-m normal incidence monochromator for wavelengths between 3000 A and 300 A (4

Superconducting 7 T wiggler for LSU CAMD.

A superconducting 7 T wiggler is under fabrication in a collaboration between Budker INP and LSU CAMD. The wiggler magnet has been successfully tested inside a bath cryostat and a maximum field of 7.2 T was achieved after six quenches. The main parameters of the wiggler and the method of the wiggler installation onto the storage ring are discussed.

Angle-resolved UV photoelectron spectra (UPS) of thin films of perylene-3,4,9,10-tetracarboxylic dianhydride on MoS(2).

Angle-resolved UV photoelectron spectra (ARUPS) were measured for thin films of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) deposited on cleaved MoS(2) surfaces. The take-off angle (theta) dependence of the photoelectron intensity of the highest pi band showed a sharp maximum at theta = 32-34 degrees. A spectral feature of the binding energy at approximately 8.9 eV, which is believed to originate from a pi state, showed a remarkably different theta dependence from that of the pi band. A quantitative analysis of the observed theta dependencies clearly indicates that (a) the feature at approximately 8.9 eV originates from the oxygen 2p non-bonding states and (b) the molecules lie flat on the substrate surface.