A line‐shape analysis of room temperature photoluminescence (PL) spectra was carried out on Si‐doped GaAs samples grown by molecular beam epitaxy. The electron concentrationnof the samples ranges from 1.0×1017to 4.2×1018cm−3. It was found that the conduction band tail &eegr;cand the Fermi energy &Vegr;fmeasured from the conduction band minimum can be expressed as &eegr;c=2.0×10−8n1/3(eV) and &Vegr;f=−0.074+1.03×10−7n1/3(eV), respectively. The PL peak energy, at which the electron concentration per unit energy in the conduction band is maximum, can also be expressed as 1.426+2.4×10−14n2/3(eV). ©1995 American Institute of Physics.