Atomic Structure of Light-Induced Efficiency-Degrading Defects in Boron-Doped Czochralski Silicon Solar Cells

Abigail Meyer, Craig Taylor, Michael Venuti, Serena Eley, Vincenzo LaSalvia, William Nemeth, Matthew Page, David Young, Paul Stradins, Sumit Agarwal

Research output: Contribution to journalArticlepeer-review

8 Scopus Citations


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. The line shape parameters linked these defects to both B and O impurities in Cz Si.

Original languageAmerican English
Pages (from-to)5416-5422
Number of pages7
JournalEnergy and Environmental Science
Issue number10
StatePublished - Oct 2021

Bibliographical note

Publisher Copyright:
© 2021 The Royal Society of Chemistry.

NREL Publication Number

  • NREL/JA-5900-79622


  • boron doped
  • Cz Si
  • Czochralski
  • electron paramagnetic resonance
  • EPR
  • LID
  • light induced degradation
  • photovoltaic
  • PV


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