Amorphous germanium recombination junctions in amorphous-silicon-based tandem solar cells

Abstract

The recombination junction between two cells in amorphous-silicon-based tandem devices can be improved by inserting doped nanocrystalline silicon layers, which have higher conductivities, between doped amorphous silicon layers. However, long deposition times (∼15 min) are required to nucleate and grow these thin nanocrystalline silicon layers on an amorphous-silicon layer. We show that by increasing the phosphorus doping in the amorphous silicon n layer, and replacing the nanocrystalline silicon layers with amorphous germanium layers, a similar performance is obtained with a shorter (∼1 min) deposition time.