Cathodoluminescence and electroacoustic detection have been used for the characterization of Be‐doped GaAs epilayers grown by molecular beam epitaxy for the doping levels greater than 6.5×1017at. cm−3. The Be concentration dependence of cathodoluminescence intensity as well as electron acoustic intensity shows the presence of nonradiative centers for concentrations greater than 1018at. cm−3. Besides, extended defects and doping striations are revealed by electron acoustic images for heavily Be‐doped GaAs (1020at. cm−3).