Recombination involving defects and impurities in monocrystalline and multicrystalline solar silicon was studied. The main techniques used were recombination lifetime mapping measurements using microwave detected photoconductivity decay and variants of deep-level transient spectroscopy. In particular, Laplace deep-level transient spectroscopy was used to distinguish between isolated point defects, small precipitate complexes and decorated extended defects. The behaviors of some common metallic contaminants in solar silicon were compared with regard to their effect upon carrier lifetime and cell efficiency. Finally, the role of hydrogen passivation in relation to transition metal contaminants, grain boundaries and dislocations was considered. It was concluded that recombination via point defects could be significant but that, in most multicrystalline material, the predominant recombination path was via decorated dislocation clusters within grains, with little contribution being due to the overall recombination arising from grain boundaries.

Recombination via Point Defects and their Complexes in Solar Silicon. A.R.Peaker, V.P.Markevich, B.Hamilton, G.Parada, A.Dudas, A.Pap, E.Don, B.Lim, J.Schmidt, L.Yu, Y.Yoon, G.Rozgonyi: Physica Status Solidi A, 2012, 209[10], 1884-93