Atomic structure of light-induced efficiency-degrading defects in boron-doped Czochralski silicon solar cells

Boron-doped Czochralski (Cz) Si is the most commonly used semiconductor in the fabrication of solar cells. The minority carrier lifetime of boron-doped Cz Si decreases upon exposure to light due to B–O-related defects, which reduce the performance of ~109 solar modules worldwide. Using electron para...

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Published inEnergy & environmental science Vol. 2021; no. 14
Main Authors Meyer, Abigail R., Taylor, P. Craig, Venuti, Michael B., Eley, Serena, LaSalvia, Vincenzo, Nemeth, William, Page, Matthew R., Young, David L., Stradins, Paul, Agarwal, Sumit
Format Journal Article
LanguageEnglish
Published United States Royal Society of Chemistry 13.08.2021
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Summary:Boron-doped Czochralski (Cz) Si is the most commonly used semiconductor in the fabrication of solar cells. The minority carrier lifetime of boron-doped Cz Si decreases upon exposure to light due to B–O-related defects, which reduce the performance of ~109 solar modules worldwide. Using electron paramagnetic resonance (EPR), we have identified the spin-active paramagnetic signatures of this phenomenon and gained insights into its microscopic mechanism. We found a distinct defect signature, which diminished when the degraded sample was annealed. The second signature, a broad magnetic field spectrum, due to the unionized B acceptors, was present in the annealed state but vanished upon light exposure. These observations show that, on degradation, nearly all the ~1016 cm–3 B atoms in Cz Si complexed with interstitial O atoms, whereas only ~1012 cm–3 of these complexes created defects that were recombination-active. The formation rate of these recombination-active defects correlated with the decay of the minority carrier lifetime. Furthermore, the line shape parameters linked these defects to both B and O impurities in Cz Si.
Bibliography:USDOE Office of Energy Efficiency and Renewable Energy (EERE)
NREL/JA-5900-79622
AC36-08GO28308; SETP DE-EE0008171; SETP DE-EE0008984
ISSN:1754-5692
1754-5706