| Nanostructuring via electrodeposition |
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The small research group led by Dr L. Philippe at the Laboratory of Mechanics of Materials and Nanostruc-tures started its scientific activities at the interface of physics and chemistry in April 2008. In our research, we use electrochemical means to create well-ordered nanostructured materials, compact layers and microdevic-es, featuring exquisitely defined geometry, controlled surface chemistry, and tunable physical/mechanical properties.
We are interested in materials and structures whose properties can be tuned or optimized by variations in size, geometry, crystallinity, composition or surface. This “make and measure” strategy is applied primarily to problems related to mechanical devices, biomedical materials, culture heritage surfaces, renewable energies and magnetism.
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Tuning crystallinity via electrodeposition
Most electroformed components are nanocrystalline and are used as mechanical elements (e.g. gear, tools, etc). UV- and electron beam lithography in combination with electrodeposition of nanocrystalline Nickel is today the only established technique to synthesize metallic MEMS and watch parts. Our research focuses on NiCo, NiP alloys and ternary compounds of Fe-Ni-Cr (stainless steel) for applications in the watch and MEMS industry. In addition, compact layer of gold are developed with specific enhanced mechanical properties with ceramic nanoparticles co-deposition.
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Optical image of stainless steel obtained by electrodeposition |
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Optical images of pure gold and gold-composites compact layers obtained with different electrodeposition conditions. |
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| Running Projects |
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| Electrodeposition of metallic nanostructures |
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| STEM images of Co nanowires and nanotubes obtained by controlled electrochemical deposition conditions |
| | For producing metallic (Co, Ni, Co, Pt, Au, etc.) nanowires and nanotubes with various functionalities (e.g. fer-romagnetic, Tip Enhanced Raman Scattering, etc.) we use electrochemical deposition process inside high as-pect ratio membrane templates (Anodic Alumina Oxide or polycarbonate). We control the main growth pa-rameters during the deposition in order to tailor crystal structure and morphology of the metallic nanostruc-tures. By using electrodeposition we are also able to synthesize multilayer, alloy and composites Moreover, their structural, electrical and mechanical properties were studied in correlation with the synthesis conditions employed. |
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| SEM images of flail Au nanostructures obtained by controlled electrochemical deposition conditions |
| | Free-template electrodeposition is used for the synthesis of metallic nano/microstructures on solid substrates in order to facilitate their practical applications as nanobuilding blocks in nanodevices. For tailoring the nanostructures and the growth mechanism, organic molecules can be added to the electrochemical bath. The use of these metallic nano/microstructures in many applications (SERS, gas sensing, wettability, etc) is studied.
Contact: Laetitia Philippe |
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| ZnO urchin like nanostructures obtained by electrochemical deposition |
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Contact: Laetitia Philippe |
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| Au nanowires deposited electrochemically into polycarbonate templates with the wire shape resembling the pore size |
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Contact: Laetitia Philippe |
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| Si nanowire arrays obtained by chemical etching of Si wafer using self-assembled polystyrene as a template |
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Contact: Laetitia Philippe |
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| Combined electrochemical and mechanical nanopatterning of semiconductor surfaces |
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| distribution of maximum shear stress during nanoscratching |
| | We investigate selective dissolution of n-InP(1 0 0) triggered by surface defects. Nanometer size grooves were produced by sensitizing an InP surface with a mechanical contact patterning technique, i.e. nanoscratching at low loading forces at the threshold between elastic and plastic contacts. Subsequently, site-selective electrochemical dissolution was triggered in acidic electrolytes. Electrochemical characterization shows that there is an onset voltage for selective dissolution at the scratch-induced defects and that it is possible to define a processing potential window where dissolution occurs only inside the nanoscratches. Scanning electron microscopy (SEM) micrographs reveal that for optimized forces, highly confined dissolution in well-defined channels of 125 nm width can be obtained. Transmission electron microscopy (TEM) cross sectional analysis of the scratches before and after electrochemical experiments shows that the dislocations generated are confined in a well-defined volume below the surface, and that exactly this dislocated volume is dissoluted. Based on contact mechanics, the lateral resolution and the morphology of the dissolved groove can be explained by the dissolution time and the tip radius and the morphology by the applied load.
Contact: Johann Michler
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| Services |
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| | We offer scientific advises on the electroplating bath development for UV-LIGA process and others. We offer advises with galvanic processes and related mechanical and structural properties to be investigated. We also have competence for anodisation processes.
We offer:
- Developed electroplating bath for UV-LIGA process
- Galvanic processes and related mechanical and structural properties.
- Anodisation processes (e.g. Al…).
- Optical properties (Transmission and reflectance) of different kind of semiconducting and metallic materials by using Spectrophotometer connected to integrated spheres.
- Photoconversion efficiency measurements (I-V curves) of solar cells using halogen light source.
- UV-lithography facility
Contact: Laetitia Philippe
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