Use of Cu/Ta2O5/Cu Fabry–Pérot cavities as large-area transparent electrodes for Si photovoltaic devices

The authors propose a sputtered (Cu/Ta2O5/Cu)/Ta2O5 layered material for dual use as antireflective coating and as a large-area electrode for silicon photovoltaic devices. We experimentally demonstrate the transparency of this metallo-dielectric material in the UV-Vis band, which improves the amount of light collected even at large angles off-the-normal. Using numerical simulations, we subsequently discuss this transparency in terms of the overlap of the Fabry–Pérot resonances with the minimum of the absorption coefficient. Furthermore, we measured the photo-response of a (Cu/Ta2O5/Cu)/Ta2O5-coated Schottky diode using an AM1.5 spectrum supplied by a solar simulator. Measurements reveal that the structure acts as a large-area electrical electrode, which reduces the overall resistance of the Si/Cu interface and improves the collection of the photogenerated majority carriers.