Six types of systematic photoluminescence (PL) surements (T ≥ 77 K) were carried out on single crystals of AlxGa1-xAs (x ~ 0.3) undoped or doped with Be by LPE or ion implantation. The multimea-surements approach was employed in order to ascertain that the highest-energy radiative recombination was in fact band-to-band (BTB), and consequently to obtain accurate activation energies. LPE doped
