Edge‐defined film‐fed growth (EFG) Si grown with carbon monoxide (CO) added to the Ar ambient during crystal growth yields solar cells with higher efficiencies than when grown without CO. This increase in cell efficiency is not fully understood. Surface photovoltage, deep‐level transient spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to determine the minority carrier diffusion lengths, impurity distributions, and defect structures in uncontaminated, Cr contaminated, and V contaminated EFG material grown with and without CO added to the Ar ambient. We conclude that ‘‘SiC‐like’’ complexes in the near‐surface region of the CO ambient material act as gettering sites during crystal growth, and that this gettering action results in lower bulk impurity levels and higher solar cell efficiencies. ©1995 American Institute of Physics.