>16% thin‐film epitaxial silicon solar cells on 70‐cm2 area with 30‐µm active layer, porous silicon back reflector, and Cu‐based top‐contact metallization

We demonstrate the use of a copper‐based metallization scheme for the specific application of thin‐film epitaxial silicon wafer equivalent (EpiWE) solar cells with rear chemical vapor deposition emitter and conventional POCl3 emitter. Thin‐film epitaxial silicon wafer equivalent cells are consisting of high‐quality epitaxial active layer of only 30 µm, beneath which a highly reflective porous silicon multilayer stack is embedded. By combining Cu‐plating metallization and narrow finger lines with an epitaxial cell architecture including the porous silicon reflector, a Jsc exceeding 32 mA/cm2 was achieved. We report on reproducible cell efficiencies of >16% on >70‐cm2 cells with rear epitaxial chemical vapor deposition emitters and Cu contacts.