A recessed structure was used on the GaAs/Si solar cells to reduce the current path.
The associated series resistance was reduced by a recessed structure.
The carrier recombination loss was improved due to pyramid-like recessed structure.
In this study, epitaxial layers of GaAs-based solar cells were grown on Si substrates using a molecular beam epitaxial system. The pyramid-like via hole recessed electrode structure was fabricated on the back side of the Si substrate to improve the performance of the resulting solar cells. Since the current path was effectively reduced by the via hole recessed structure, the associated series resistance and the carrier recombination loss of the resulting GaAs/Si solar cells were decreased. Consequently, the conversion efficiency enhancement of 21.8% of the GaAs/Si solar cells with the via hole recessed structure was obtained due to the improvement in the short-circuit current density and the fill factor compared with the conventional GaAs/Si solar cells.