An improved silicon-oxide-based intermediate-reflector for micromorph solar cells



In this paper, we report on the development of an n-type silicon oxide intermediate reflector (SOIR) for a-Si:H/µc-Si:H tandem solar cells produced in an industrial-type AKT1600 PECVD reactor. A comparison to a tunnel recombination junction with µc-SiOx in the p-layer is made. Lower fill factors, resulting from the implementation of the SOIR, could be avoided by the deposition of a thin n-doped microcrystalline silicon (µc-Si) recombination layer after the SOIR. A cell efficiency of 9.5% after 168 h of light soaking at 50 °C and 1 sun was reached on commercially available SnO2:F front TCO, which is a 2% relative increase over a similar cell without the SOIR. Possible explanations for the role of this recombination layer are discussed (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)