At present, there are two separate research activity is going on in the group. One area is focused on Biotechnology related research. Another area is focused on Nanotechnology research.
Topic: Magnetologic and sensing devices fabricated by electron beam induced deposition (EBID).
Researcher: Marco Gavagnin
3-dimensionally designed magnetic nanostructures are attracting tremendous attention in last few decades due to their potential application in magnetic sensors and magnetologic (ML) devices. ML is rising as a new computational nanotechnology based on magnetic phenomena, allowing to overcome power consumption limitations of the existing CMOS-based digital logic. ML requires the use of advanced synthesis techniques which permit to grow arrays of nanostructures with high spatial resolution and exceptional geometry control. In this project magnetic nanowires are fabricated by electron beam induced deposition (EBID) as basic elements for ML technology. EBID is a maskless, resistless direct-write method that is capable to perform a locally confined chemical vapor deposition initiated by a focused electron beam
In order to know the chemistry, morphology and topography of the so obtained nanostructures energy dispersive X-ray spectroscopy (EDXS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) investigations are performed respectively. As main investigation technique for the magnetic properties of such small systems magnetic force microscopy (MFM) studies are carried out. MFM is performed in a commercial atomic force microscope using magnetized probes which reveal the magnetic forces rising from the sample surface (Fig. 2). The MFM probes are realized by modifying commercial available AFM tips by EBID.
The fast processing time and the unique properties of EBID nanostructures represent a step forward for both nanofabrication and characterization of magnetologic computational devices.
Topic: Focused Electron Beam Induced Deposition of noble metals
Researcher : Mostafa Moonir Shawrav
Focused electron beam induced deposition (FEBID) is a direct writing technique for novel materials. Due to the nanometer precision of material deposition this maskless & resistless method has received increasing attention. The goal of this project is the deposition of noble metal nanomaterials such as Au, Pt, Pd, Rh. These materials are of importance for chemically inert electrical contacts, as chemical catalysts and as anchors for self-assembled monolayers.
This unique method will be used with organometallic precursors to deposit noble metals. The precursor previously adsorbed from the gas phase will be dissociated in the focus of an electron beam. This electron beam will be provided by a scanning electron microscope. At first, precursors will be used to investigate the impact of different process parameters including scanning parameters (dwell time, refresh time) and beam parameters (beam current, acceleration voltage), as well as gas flux and substrate temperature. As a standard precursors Dimethyl (acetylacetonate)gold(III) precursor will be used and act as reference for other precursors to be used. The Au deposition process shall be optimized for high material purity and high deposition rate. A four terminal I-V measurement probe station will be used to determine the electrical properties of the structures. Atomic Force Microscope, Transmission Electron Microscope, FIB-cross-section analysis with different other characterization techniques (EDX, XPS) will be used to characterize the deposited structures. This data will provide the bias to conclude on the involved reaction mechanisms.
Furthermore, in a post-deposition process, carbon shall be removed with one of the following approaches: annealing in oxygen, plasma etching or wet etching in sulfuric acid. The long term goal would be deposition gold nanomaterials for bonding with Self Assembled Monolayers. Apart from gold also precursors provided by the ENHANCE consortium member will be used for nanomaterial deposition.
Topic: Neuronal electrical activity measurements of isolated neurites using multi-electrode arrays
Researcher: Johann Karl Mika
Description: Extracellular recording of neural activities is a powerful tool in neuroscience to investigate the communication within neural cell cultures. The extensive and complex wiring in cell cultures makes it very difficult to observe and analyze neural electrical behavior of individual neurons. A versatile platform that allows direct electrical measurement of extracellular potentials originating not from neuronal networks but from isolated axons from dissociated neural cell cultures will be the focus of research. This platform consists of a microstructured axon isolation device (AI) device aligned and mounted atop of a microelectrode array (MEA). The setup facilitates specific electrical recording of neural activity of well-identifiable axons. The proof of isolated axon growth will be performed with sympathetic neurons from the superior cervical ganglion of P5 WT mice grown on the AI-MEA platform. Due to the transparent structure of the device, electrical recordings will be correlated with the optical observations. The benefit of the presented approach is the capability to design the whole platform to the requirements of the experiment. The presented platform will facilitate neurological studies where axons and somata can be treated independently of each other.