From free-carrier absorption measurements of spatially and temporally resolved excess carrier concentrations in the n-base of electron irradiated, low doped, highly injectedp-i-ntype diodes, the effective ambipolar lifetime has been extracted with respect to different injection levels and temperatures. By measuring lifetimes up to injection levels of3×1017cm−3, the ambipolar Auger coefficientCaand its temperature dependence has been determined in the range of 300–420 K. In accordance with recent publications, the room temperature value of the Auger coefficient was found to be about three times higher than one of the most commonly used values. Further on, the ambipolar Auger coefficient is empirically estimated to vary with temperature asCa(T)=1.1×10−30(T/300)1.8, wereTis the absolute temperature. Also the ambipolar diffusion coefficient has been investigated and compared with different models. The results are important and useful in simulation of high-injected silicon devices, i.e., solar cells and power devices. ©1997 American Institute of Physics.