Upgraded metallurgical-grade silicon solar cells with efficiency above 20%

P. Zheng, F. E. Rougieux, C. Samundsett, Xinbo Yang, Yimao Wan, J. Degoulange, R. Einhaus, P. Rivat, D. Macdonald

Research output: Contribution to journalArticlepeer-review

24 Scopus citations


We present solar cells fabricated with n-type Czochralski-silicon wafers grown with strongly compensated 100% upgraded metallurgical-grade feedstock, with efficiencies above 20%. The cells have a passivated boron-diffused front surface, and a rear locally phosphorus-diffused structure fabricated using an etch-back process. The local heavy phosphorus diffusion on the rear helps to maintain a high bulk lifetime in the substrates via phosphorus gettering, whilst also reducing recombination under the rear-side metal contacts. The independently measured results yield a peak efficiency of 20.9% for the best upgraded metallurgical-grade silicon cell and 21.9% for a control device made with electronic-grade float-zone silicon. The presence of boron-oxygen related defects in the cells is also investigated, and we confirm that these defects can be partially deactivated permanently by annealing under illumination.

Original languageEnglish (US)
Article number122103
JournalApplied Physics Letters
Issue number12
StatePublished - Mar 21 2016
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2016 AIP Publishing LLC.

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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