We propose a method for the quantitative evaluation of electron-beam-induced current profiles measured in normal-collector geometry across p-n junctions in GaAs/Al0.4Ga0.6As heterostructures. We obtain a theoretical expression, valid for all distances from the junction, and which takes into account the spatial extension of the electron-hole pairs generation. From the comparison of calculated with experimental profiles, we evaluate the minority carrier diffusion length and to some extent the surface recombination velocity. (C) 1996 American Institute of Physics.