The electrical performance of Be‐doped,p‐p+GaAs homojunction barriers is characterized and analyzed. The results of the analysis show that minority‐carrier electrons, at 300 K, have a mobility of 4760 cm2/V s at a hole concentration of 2.3×1016cm−3, and that the effective recombination velocity for these homojunction barriers is about 6×104cm/s. We present evidence that this unexpectedly high recombination velocity is a consequence of an effective reduction in band gap due to the heavy impurity doping. The effective band‐gap shrinkage in this Be‐doped material grown by molecular‐beam epitaxy appears to be comparable to that already observed for Zn‐doped GaAs grown by metalorganic chemical vapor deposition. This work demonstrates that so‐called band‐gap narrowing effects significantly influence the electrical performance of GaAs devices.