Institute of Solid State Physics
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SS22 WS22 SS23 WS23 SS24 WS24 Guidelines for Master Students
SiC Nanoparticles from Laser Ablation of Sol-Gel Prepared Materials for Hybrid Solar Cells Silicon carbide (SiC) is an interesting material for a lot of different fields, ranging from high power electronics, as high temperature stable wide-band gap semiconductor, to material engineering, with its high Mohs hardness of 9.6 and little sensitivity to degradation. One novel application of special interest is using SiC as potential electron acceptor in organic hybrid solar cells. Presently used materials for this purpose are dominated by lead or cadmium-based compounds, which show high toxicity, whereas SiC is much more environmentally friendly, even a bio-compatible alternative. In this study, we present a novel bottom-up approach for preparation of suitable nanocrystalline SiC for integration in organic semiconductor films. This material is obtained by a sol- gel-based and carbothermal reduction-assisted method, in combination with laser ablation. The process is suitable for the fabrication of doped cubic polytype material in the nano-to microscale. To gain nanocrystals (NCs) in a distinct size range, which allows quantum confinement and accordingly tuning of the bandgap by changing the size of the NCs, laser ablation is used. The combination of these two methods allows an easier and more cost efficient fabrication of SiC NCs compared to commonly used top-down methods like wet-chemical etching of commercial SiC wafers with hydrofluoric acid. We show first results on the properties of the obtained NCs, depending on the chosen process parameters. The shape and crystal structure of the fabricated NCs from investigations by electron microscopy and X-ray diffraction will be shown. Photoelectron spectroscopy techniques were adopted for the determination of the surface termination and chemistry (XPS) and relevant band energies (UPS). Finally, an estimation of defect densities and photophysical properties will be given, which are important criteria for their applicability in hybrid solar cells. |
