While photolithographic techniques are well established for patterning of semiconductors, they have not been employed for polysaccharide based materials to a large extent. The main idea of this project is to generate nano-patterned cellulose thin films using ideas and concepts from semiconductor industry to create 2 and 3 dimensionally structured cellulose surfaces. As starting material for the generation of cellulose surfaces, trimethylsilyl cellulose (TMSC) containing (2-photon sensitive) photoacid generators (PAG) is used which is deposited on different kinds of surfaces by spin coating. The use of mask aligners and UV-light or 2-photon absorption lithography converts exposed areas to cellulose (silyl groups are cleaved off by the generated acid) while in the unexposed areas TMSC remains. After the patterning step, TMSC can be selectively dissolved using an appropriate solvent or, alternatively, the converted cellulose can be digested using cellulases. Using the latter route remaining TMSC can be converted to cellulose in an additional step. As a result, 2 and 3 dimensionally nanostructured films can be obtained which have a large potential as material for semiconductor industry, in medicine (for growth of stem cells, antifouling materials) and in optical materials (refractive index changes). While the main focus of the project is to generate nano-structured cellulose films, this approach can be easily extended to other polysaccharides as well. The whole project aims at reducing organic solvents and to use mainly so-called eco-solvents.

New techniques in far-field fluorescence microscopy have improved optical resolution down to several times the diffraction limit. The resolution currently achieved with these techniques is 28 nm. Recently it was proposed that fluorescent reversible molecular compounds ('photoswitches') could be utilized in fluorescence microscopy, allowing, in principle, to improve the resolution up to molecular dimensions, i.e. 1-5 nm. The use of these photochromic compounds should enable the utilization of very low light intensities, thus making the technique particularly suitable for biological applications.It is proposed to investigate the feasibility and performance of photochromic fluorescent compounds in modern far-field fluorescent microscopy techniques, as well as explore its different potential uses and applications. The aim of this project is to improve resolution to a few nanometers and, in particular, apply the technique to live-cell imaging as well as to memory storage and lithography.Undertaking this scientific project in a field’s leader's laboratory will give me the opportunity to learn advanced microscopy techniques, and acquire a significant experience and expertise in the field. After having completed my training in Germany, I will be prepared to set up a research team and start an independent research career in my home country, Argentina.

The goal of the project is the development of a novel analytical tools allowing in-vivo speciation of metal-protein complexes. The interest in this topic is driven by the fact that this information turns out to be crucial for the understanding of the molecular mechanisms of metal transport, chelation, and biotransformation which govern the bioavailibility of the metal and resistance of an organism to metals present in high concentrations in the environment. There is sufficient evidence in human for the carcinogenicity of cadmium and cadmium compounds; therefore the project is focused on the detection and characterization of proteins that are molecular targets for cadmium in model organisms such as Arabidopsis thaliana. The analytical tools are going to be based on two complementary approaches. In the first one, consisting of in vivo screening for a non-denaturating 2D gel electrophoresis, laser ablation ICP MS detection will be developed. In the alternative approach, a library of proteins of an organism will be created by the conventional (denaturating) 2D electrophoresis and made react with cadmium. For screening the library, electrophoresis on a chip coupled with ICP MS via a dedicated nanonebulizer will be developed for the high-throughput detection of the metal-protein complexes in the biological environment. Structural information of cadmium-protein will be obtain by use of molecular mass spectrometry MALDI-TOF (matrix assisted laser desoption ionization time-of flight) MS and ES (electrospray) MS/MS.

The objective of the proposal is the fabrication and study of three dimensional (3D) magnetic nanowires for ultra-high density information storage. Current memory architectures are 2D, composed of one layer of active components. The extension of data storage devices into the third dimension could result in information densities of hundreds of Gb/in2, causing a technological revolution. The project aims at implementing a 3D version of the existing 2D host institution’s idea of domain wall based shift registers to store data. In this scheme, the data bits are stored using the two possible directions of the magnetisation in thin and narrow nanowires made of soft ferromagnetic materials. The fabrication of the 3D devices will be done by using a novel promising nanolithography technique: focused electron beam induced deposition (FEBID), with unique capabilities for the creation of 3D nanostructures. We have recently demonstrated the required possibility to control domain walls in cobalt nanowires created by this technique. The patterning of magnetic nanostructures by means of conventional lithography, such as electron beam lithography and ion milling, will be explored in parallel. The control of the domain walls will be probed by magneto-optical magnetometry and magneto-electrical measurements. The two directions to be investigated for the creation of 3D magnetic devices will be the stacking of 2D magnetic nanowires, and the direct fabrication of 3D nanowires. The host group possesses patents protecting the ideas presented in this proposal. The success of the project would place the European Union in a privileged position to lead the next steps in the development of Information Technology.

Laser Ablation-ICP-MS has become the most important and successful technique for direct elemental analysis in solids, including: silicate samples, nano tubes, glass, metals, archaeological samples, etc. Despite this, recent studies in LA-ICP-MS show that all three individual processes during sampling and detection (ablation, aerosol transport and vaporization, atomisation and ionisation) are distinct sources of elemental fractionation and can lead to inaccurate quantification. Therefore, any reduction in elemental fractionation will significantly improve the future applications of this technique.Research shall be carried out to describe the composition of the aerosol after ablation, during transport and within the ICP-MS. The main goal is to understand the various processes involved in LA-ICP-MS to achieve representative sampling, transport and excitation of laser-induced aerosols for quantitative analysis using non-matrix matched calibration standards. At present, a transport efficiency of 10 % of the laser-generated aerosol and the vaporization and ionisation efficiency of 2-3 % of the total introduced mass into the ICP represent a severe loss of valuable analytical information and leads to problems in quantification. Therefore, the aerosol formation and transport processes need modifications, which will be studied by direct gas phase reactions of theablated material using different gas combinations to enhance sample transport.Our research will also focus on fundamentals of 266 nm femtosecond laser ablation. Such a system will be established and used for aerosol production studying the capabilities of non-thermal ablation processes. The fs-laser ablation process leads to less thermal treatment of the ablated material, which is expected to create a more representative aerosol and a smaller average particle size distribution that is more efficiently vaporized and ionized within the ICP-MS.

Two-photon direct laser writing (DLW) lithography is a powerful tool to fabricate 3D structures with feature sizes of ~100 nm. This technique is based on the quadratic dependence of the absorption of near-infrared (NIR) light (two-photon absorption, 2PA) by molecules called photoinitiators which trigger the photopolymerization of curable resins. With the aim of downsizing the structures to the nanometer resolution, a requirement of the microelectronics industry, a new strategy has been added to the DLW lithography, the two-beam approach (excitation and inhibition beams) based on the reversible saturable optical fluorescence transition (RESOLFT) concept. This approach is borrowed from the field of super-resolution fluorescence microscopy and consists in the reversible depletion of some intermediate excited state of the photoinitiators only at some specific areas of the point spread function (PSF) of the excitation beam. The objective of this project is to further develop the two-beam DLW lithography to make it more competitive compared to other advanced nanofabrication techniques. The project is conducted to overcome the limitations of the two-beam DLW lithography: 1) the large feature size, the state-of-the-art has recently been pushed to 9 nm line width from a previous value of 55 nm, and 2) the large spatial resolution (Abbe´s resolution limit) due to the so-called 'memory effect', this value always exceeds 2–5 times the feature size, with a lowest value of 52 nm. The approach is based on the investigation of the photophysics and photochemistry involved in the photopolymerization by means of the ultrafast transient absorption spectroscopy to shed some light on the inhibition processes. The expected results are the decrease of the actual size of the written features to the real nanometer resolution, ~1 nm and even more important to reduce the minimal distance of two adjacent yet separated lines (spatial resolution) to the same order of the feature size.

The aim of the present project is to explore different synthesis strategies to obtain silicon nanocrystals and carbon nanodots with luminescent properties as alternative to conventional fluorescent biomarkers or other light-emitting semiconductor nanoparticles containing heavy metals known as quantum dots. Nanostructured silicon can provide appealing properties such as size and wavelength-dependent luminescence emission in the red/near infrared window, resistance to photobleaching, and robust surface chemistry for grafting of bio-molecules without incurring the burden of intrinsic toxicity or elemental scarcity of quantum dots. Carbon-based nanostructures with fluorescent properties remain relatively unexplored but similar behaviour and properties can be envisaged. The production of silicon nanocrystals will be approached by means of two different methods: i) thermal processing of silesquioxanes to produce an encapsulating oxide matrix for the silicon nanocrystals and ii) laser pyrolysis of silicon precursors either in gas phase or in the form of aerosols containing organometallic precursors. Both methods are quite novel and offer great possibilities for scaling up the batch production of silicon nanocrystals offered by current methodologies. Likewise, the synthesis of carbon nanodots will be explored by both thermal decomposition and laser ablation of carbon-containing precursors. To stabilize the nanoparticles and render them biocompatible for in vitro and in vivo diagnostic imaging experiments, different passivating and encapsulating agents like alkyl or alkoxy-groups and micelle-forming polymers and phospholipids will be evaluated. Finally, fluorescent labelling of cells, evaluation of cytotoxicity, drug-loading, circulation and degradation of selected samples will be carried out.

High-order harmonic generation (HHG) is an increasingly used and promising technique for achieving the extreme ultraviolet (XUV) spectral range with highest brightness, short pulse duration, and coherence. Extensive studies of this phenomenon have been mostly carried out using jets of neutral atomic gas, which have resulted in novel coherent XUV sources. However, typically observed high-order harmonics presently have the disadvantage of low conversion efficiency (10-6). This is problematic for many potential applications of HHG radiation including XUV coherent diffraction imaging, time-resolved measurements, and seeding of Free Electron Lasers. Recent studies have shown that this weakness can be partially overcome by using the ablated plasma as a nonlinear medium. An especially interesting observation, unique for harmonics originated both from gas jets, surfaces, or plasma, is the enhancement of a single harmonic, attributed to resonance with a strong radiative transition. In this way, conversion efficiencies higher than 10-5 from the pump laser radiation to the harmonics in the plateau range have been reported. The project is aimed at the enhancement of HHG efficiency from laser ablation produced on the surfaces of solid-state materials and comparison with HHG from gas jets. The milestones of the proposed investigations include (a) analysis and optimization of harmonic generation from laser plasma produced on the surface of various targets, (b) search of resonance-induced enhancement of single harmonic in the XUV range, (c) harmonic generation from the laser plumes containing nanoclusters, (d) search of the continuum in the harmonic emission near the cutoff (a characteristic signature for attosecond pulse generation), and (e) HHG from gas jets and comparison with the HHG from laser plasma. As a result of project, further improvements of the harmonic efficiency in the XUV range through the HHG from laser plasma and gas jets will be achieved.

This research program aims at pioneering and developing new nanofabrication techniques for carbon-nanoelectronics using a so-called 'bottom-up' approach. Individual building blocks for carbon-based nanodevices, such as catalyst nanoparticles, horizontally aligned carbon-nanotubes and ultra-scaled contacts and dielectrics will be precisely placed directly on the chip, without the use of lithography. This will be accomplished by using unique combinations of electron-beam induced deposition (EBID), atomic layer deposition (ALD) and oblique ion beam treatments. The process development will go hand-in-hand with atomic level understanding of the developed processes using in-situ and ex-situ analysis techniques to ensure process reproducibility and selectivity.

The rapid development of novel nanoelectronic devices utilizing the spin degree of freedom of the charge carriers and thus reaching beyond the limitations of traditional semiconductor based technologies is one of the central issues in nowadays spintronics. A special emphasis is put on the fabrication and investigation of hybrid nanostructures exploiting the complementary benefits of metallic, semiconducting, magnetic as well as the recently explored, low dimensional carbon based systems (carbon nanotubes, graphen). The proposed project aims to design various hybrid nanostructures defined by optical and electron beam lithography and to develop novel schemes for determining spin-related material parameters (g-factor, spin diffusion length, spin-injection efficiency and spin transfer torque) via transport measurements. This is essential in order to explore electron spin dynamics, decoherence and relaxation for multifunctional applications (fast switching elements, combined logical and storage devices, quantum dot based semiconductor spin qbits) and to determine conditions for coherent spin-transfer in nano/micro-circuits as well as methods of detection of spin currents. These experiments help to understand and control the coherent spin states of individual charge carriers, which is fundamental for the field of quantum computation in a solid state environment. The host institute possesses all the necessary nanofabrication facilities and the high-end cryogenic background for the successful implementation of device fabrication and low-level magnetotransport measurements. The host has also pioneered the measurement technique for determining spin-polarization and spin transfer torque in nanoscale magnetic systems with a resolution down to the scale of atomic junctions.