Enhanced Carrier Collection observed in Mechanically Structured Silicon with Small Diffusion Length

• The diffusion length of minority charge carriers in the silicon bulk Ldiffis an important characteristicof optoelectronic devices fabricated from low cost silicon wafers. In this study computer simulationshave been carried out to calculate the beneficial effects of a macroscopic surface texturization on thecharge carrier generation and the collection probability. Textured solar cells should be able tocollect charge carriers more effectively resulting in an increased current due to the special emittergeometry resulting from the texture, decreased reflection losses, and the inclined penetration of thelight. In order to prove this expected behavior, deeply V-textured solar cells have been processedand characterized on low cost silicon reaching an Ldiffof about 25 mm. Spatially resolved highresolution measurements of the internal quantum efficiency exhibit a strongly increased signal in thetexture tips which is the first experimental proof of the increased charge carrier collectionprobability of deeply textured solar cells. This effect can further be seen in cross sectional electronbeam induced current measurements and the mechanical texture results in an overall gain in shortcircuit current density of about 11% and in efficiency of about 8% relatively.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

silicon solar cell texturing LBIC

Physics

Fysik

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