Ga co-doping in Cz-grown silicon ingots to overcome limitations of B and P compensated silicon feedstock for PV applications

In this paper, we investigate gallium co‐doping during CZ crystallization of boron and phosphorus compensated Si. It is shown that the addition of gallium yields a fully p‐type ingot with high resistivity despite high B and P contents in the silicon. Segregation of doping impurities is consistent with theory. Minority carrier lifetime and majority carrier mobility measurements indicate that this material is suitable for the realization of solar cells with comparable efficiencies to standard material. Significant light‐induced degradation of minority carrier lifetime is however revealed to occur in this material. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)