GROWTH AND SOLAR CELL ASPECTS IN RELATION TO POLYCRYSTALLINE SILICON RIBBONS GROWN BY THE RAD PROCESS
It is reported on the results of an 18-month research effort supported in part by the present CEC contract and AFME contract no 82.11.092.2596, on the growth of polycrystalline silicon ribbons by means of the RAD process. The main objective of this contract period were the demonstrations of a pull length up to 50 m at 10 cm/mm and of AM1 conversion efficiency of 10 % on 50 cm**2, A.R. coated cells. The progress of this research was slowed down by delays in controlling the geometrical aspects of the carbon ribbon. Indeed, deviations to geometrical specifications, namely flatness and straightness, prevented long duration growth and the achievement of large sized, flat layers. Nevertheless, ribbons up to 30 m in length have been grown at 10 cm/mn with a total thickness of around 140 to 170 mum. Crack-free sheet pieces up to 100 cm**2 in size and as thin as 50 mum thus obtained were successfully separated from the carbon ribbon by means of burn-off step at 1000 degrees C in oxygen. Solar cells made from this material have typical conversion efficiencies in the 10 to 12 % range ; the conversion efficiency does not appear to depend on the pull rate in the 5 to 10 cm/mn range. Finally, hydrogen passivation using a Kaufman ion source resulted in a large increase of the mean value of the conversion efficiency and in a narrowing of its distribution. The best cell thus treated has a conversion efficiency of 15.5 % (2 cm**2 in size).
Bibliographic Reference: EUR 9978 EN (1985), MF, 110 P., BFR 330, BLOW-UP COPY BFR 550, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989124046000 / Last updated on: 1987-01-01
Available languages: en