Nanostructured SIS solar cells

Due to their electrical conductivity and transparency in the visible spectral range, transparent conductive oxides (TCOs) are suitable as transparent front electrodes for multiple cell concepts. One promising device is a semiconductor-insulator-semiconductor (SIS) solar cell, in which the TCO induces the pn juntion and acts as a transparent electrode at the same time. Due to its work function, the thin TCO layer leads to the inversion of the subsurface region. The high refractive index of transparent conductive oxides enables antireflection coating in a limited spectral range. One approach to achieve broadband antireflection properties with effective light coupling into the absorber is a nanostructured silicon interface. For large area modifications of silicon, the inductive coupled plasma (ICP) etching technology is a possible technique. The combination of the nanostructured surface and the SIS system leads to a novel solar cell concept with promising properties and a simple production process. In our study, we used pulsed dc magnetron sputtering for the deposition of thin ITO films on p-doped unstructured and ICP-structured silicon substrates. Optical and structural properties have been analyzed. Furthermore, the solar cell performance of the first devices under AM1.5G illumination will be shown and discussed.