Present state of S-web SI ribbon manufacture, solar cells and modules

With the S-Web technique Si can be produced directly in form of thin plane ribbons with high throughput. In our laboratory pulling unit S-Web Si ribbons with a width of 6 cm have been grown at a speed of about 1 m/min. The efficiency of test solar cells made of such ribbons with polished surface is eta equal or smaller than 11.7%, with as grown surface equal or smaller than 11.2%. A module sized 50 cm x 50 cm made of cells 10 cm x 5 cm has an active area efficiency of eta bigger than 10% and delivers 16.2 W sub rho. Investigations indicate that the efficiency presently is limited by the carbon and oxygen contents. In a recently installed new pulling apparatus ribbons with a width of 11 cm and a length of about 5 m have been grown at a pulling speed of up to 200 cm/min. The efficiency of test solar cells is eta = 10%. Future work concentrates on the development of a continuously working pulling process in this apparatus

Manufacture of SI ribbons by the S-WEB-technique

The S-Web technique was developed for the high-throughput production sheet Si for low cost crystalline solar cells. A pilot unit was installed to demonstrate continuous Si ribbon growth. With this machine Si ribbons have been grown continuously at a speed of 1 m/min up to a length of 145 m; the width was 11-12 cm. A maximum pulling speed of 2 m/min has been achieved. Test solar cells of S-Web ribbons pulled with a laboratory unit have efficiencies up to bigger than 12%, large area standard cells have efficiencies of up to 9,8%. A module made of such standard cells had a mean cell efficiency of 9%