Research Group Nanowires
Silicon nanowires are a new material for solar cells, sensors, and TERS.
- TEM image of a single crystalline silicon nanowire
We prepare silicon nanowires in a diameter range from several 10 to several 100 nm by the VLS process (vapor-liquid-solid growth). As deposition methods for silicon we use CVD, electron beam evaporation, and pulsed laser deposition. The VLS process starts from a nanotemplate system (mostly Au).
- Silicon nanowires produced by electron beam evaporation
If silicon (as SiH4 in CVD, or Si atoms in the other methods) is supplied, it dissolves in the template to first form a liquid eutectic droplet. This gets supersaturated with Si, which then precipitates in form of a nanowire with a diameter similar to the template droplet. The nanowires are single crystalline. Depending on the substrate they grow epitaxial on a wafer or on a laser crystallized silicon thin film, or without preferred orientation on glass.
We use the nanowires for developing a new type of thin film solar cell: The nanowires act as absorber and at the same time as a perfect light trapping device.
In the Optical Fiber Systems Department our nanowires are used for sensor development.
- Nanowire on a AFM tip
Mounted or grown on an AFM tip a nanowire with a gold droplet on top acts as a perfect TERS tip.
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