• Silicide Contacts in Solar Cells

    One of the most difficult parts of solar cells are the generation of appropriate ohmic contacts. Using dopant segregation during nickel silicidation enables contacting emitters with almost arbitrary dopant concentration. In turn, this allows optimizing the emitter with respect to lowest recombination.
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  • 2D Materials

    Two-dimensional material such as graphene and transition metal dichalcogenides are currently attracting an increasing attention. The reason is the ultrathin body thickness allowing for the realization of ultimately scaled FET without sacrificing electrostatic integrity. At the same time, they can be patterned with planar technology. In addition, heterostructures can easily be fabricated enabling an engineering of desired electronic properties.

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  • Carbon-based Transistors

    To investigate carbon-based materials (mono- and bilayer graphene, carbon nanotubes) for advanced nanoscale field-effect transistors we fabricate buried triple- and multi-gate structures that enable the generation of a potential landscape in the direction of current transport. This is used to study e.g. band-to-band tunneling in these materials as well as alternative device concepts.

  • Si/SiO2 Multilayers

    Multilayer structures consisting of Si/SiO2 are used in 3rd generation solar cells. Quantum confinement in the Si layers is used to tune the effective band gap to the desired size enabling an absorption of UV light while minimizing relaxation losses at the same time. The transmission electron micrograph clearly shows that continuous layers of Si and SiO2 with thicknesses down to 3nm can be grown.
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  • Steep Slope Transistors

    Tunnel FETs (TFET) potentially offer a superior switching behavior compared to conventional transistors and have been intensively investigated in recent years. Optimization of the device performance is studied both experimentally as well as with simulations at our institute. The image shows the local density of states in a TFET enabling a high current injection into the channel.
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  • Solar Cell’s Surface Texturing

    The surface of solar cells is usually textured in order to suppress specular reflection of incident light yielding a significantly improved light to electricity conversion efficiency. The image shows a scanning electron micrograph of a typical texturing of a crystalline silicon solar cell.
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