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Macroporous Si as an absorber for thin‐film solar cells
Author(s) -
Brendel Rolf,
Ernst Marco
Publication year - 2010
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.200903372
Subject(s) - passivation , wafer , materials science , absorption (acoustics) , etching (microfabrication) , layer (electronics) , doping , optoelectronics , oxide , current density , solar cell , carrier lifetime , range (aeronautics) , optics , silicon , analytical chemistry (journal) , nanotechnology , composite material , chemistry , metallurgy , physics , quantum mechanics , chromatography
We separate 15 μm to 32 μm thick macroporous Si films from n‐type crystalline Si wafers by electrochemical etching under back‐side illumination. These layers are surface passivated and have openings in the oxide, for local doping and contacting, over 1% of the cell area. We measure effective lifetimes within a range of 2 to 3 μs. With an analytical model for the effective lifetime in macroporous Si we find an average surface recombination velocity of 75 cm/s, dominantly caused by the contact openings. The measured optical absorption of a 26 μm thick layer allows for a maximum short circuit current density of 37 mA/cm 2 . The potential efficiency with the current surface passivation quality is 17%. The material loss for separating the macroporous absorber from the wafer is 5 μm. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)