Beryllium doping levels of up to 2.25 X 10(20) cm-3 in GaAs layers grown by molecular beam epitaxy (MBE) have been obtained at a high As/Ga flux ratio. The heavily doped p-type layers have mirrorlike surfaces and their root-mean-square roughness values do not significantly change as the hole concentration is increased. The mobility data show that the quality of the MBE layers is comparable to those prepared by liquid-phase epitaxy and vapor-phase epitaxy. Photoluminescence data confirm their high quality. In addition, the main emission line, attributed to transitions involving Be acceptors on Ga sites, shifts to a lower energy around 1.4628 eV as the hole concentration is increased to 2.25 X 10(20) cm-3, due probably to degeneracy.