Effective electron mass in heavily doped GaAs in the ordering of impurity complexes

Spectra of edge photoluminescence (PL) at 300 K have been studied in a set of Czochralski-grown Te-doped GaAs single crystals with a free carrier density of n₀=10¹⁷–10¹⁹ cm^?3. The carrier density dependences of the chemical potential and band gap narrowing are obtained by analyzing the PL spectral line profiles. The dependence of the effective mass of electrons at the bottom of the conduction band on their density, m ₀ ^* (n₀), is calculated. It is shown that the nonmonotonic m ₀ ^* (n₀) dependence correlates with data on electron scattering in the material under study and results from the ordering of impurity complexes.