INVESTIGATION ON ION IMPLANTATION AS A TECHNIQUE SUITABLE TO FABRICATE HIGH EFFICIENCY SILICON SOLAR CELLS
n+/p supersaturated solar cells were fabricated by using ion implantation and pulsed laser annealing. With these techniques it is possible to obtain emitters which are doped well beyond the solubility limit and present lower sheet resistivities for equal junction depth. In fact, the cells produced in this way presented a low series resistance, but, the higher the emitter doping was, the lower was the conversion efficiency. Measurements of diffusion length, quantum efficiency and reflectivity allowed us to demonstrate that the supersaturated layers are characterized by high values of the absorption coefficient, which are two orders of magnitude higher than in the low doped silicon (for the wavelength of 0.9 mum). Moreover, reflectivity measurements evidenced a considerable decrease of this parameter for the very high concentration examined. The dramatic increase of the absorption in the emitter region, where it is well known that the collection efficiency is in any case very low, determines a poor short circuit current and consequently a low conversion efficiency of the solar cells.
Bibliographic Reference: EUR 8215 EN (1984) MF, 83P., BFR 120, BLOW-UP COPY BFR 415, EUROFFICE, LUXEMBOURG, POB 1003
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Record Number: 1989122075900 / Last updated on: 1987-01-01
Available languages: en