Germanium-doped Czochralski silicon: A novel material for solar cells

The effect of Ge codoping on the light induced degradation (LID) of B doped Czochralski-silicon (CZ-Si) was investigated. The rate of degradation under illumination is relatively suppressed in B and Ge codoped Czochralski-silicon (CZ-Si) compared to B-doped CZ-Si. The O_i concentrations measured by FTIR spectroscopy was decreased as the Ge concentration increased in the Si crystal. The formation of Ge-VO complex in silicon lattice is considered as a possible reason for the variation in O_i. Moreover, the compressive strain field around the Ge-VO complex may increase the barrier for O diffusion which limits the formation of fast diffusing O dimmers. As a consequence, the B-O dimmer (O_2i) related defects were relatively suppressed, which causes the suppression of LID effect in B and Ge codoped CZ-Si.