The MBE growth conditions for Be doped GaAs layers are evaluated from quantum efficiency of the negative electron affinity photocathodes made of these layers. The quantum efficiency of the GaAs layers grown by molecular beam epitaxy method at various growth conditions was measured in reflection mode operation. High quantum efficiencies were obtained with Be doping levels between 10¹⁸ and 10¹⁹ cm^-3 at high As/Ga beam flux ratios and high substrate temperatures.