Photoluminescence (PL) spectra of beryllium δ -doped GaAsAlAs multiple quantum wells are studied over a range of doping concentrations. Possible mechanisms for carrier recombination, both above and below the Mott metal-insulator transition, are discussed. In 15 nm width Be δ -doped GaAsAlAs quantum wells, it is found that the Mott transition can be observed if the acceptor concentration (NBe) 3× 1012 cm-2. At doping concentrations near the Mott transition band the PL spectra are dominated by excitons-bound-to-acceptor impurity recombinations. Above the Mott transition, the radiative recombination of free electrons with a two-dimensional hole gas is found to be the dominant recombination mechanism.