Silicon solar cells with polysilicon emitters and back surface fields

The first solar cells using in-situ doped polysilicon contacts to form both emitter and back surface field (BSF) regions are reported. The use of polysilicon contacts permits extremely low thermal budget processing (maximum 850°C 5 sec for dopant activation), preserving substrate properties. The effectiveness of the BSF is best seen with backside illumination, where the photocurrent under natural sunlight is found to be over 30% of that obtained with frontside illumination, even though the substrate thickness is comparable to the minority carrier diffusion length. The applicability of the structure to bifacial operation is considered.

• View at Publisher
• View at Scopus