The luminescence of GaAs layers grown by molecular beam epitaxy at low substrate temperature (230 °C) in a GaAs/In0.2Ga0.8As multiple quantum well structure is presented. The near‐band‐gap emission and defect‐related emission are observed for samples annealed at high temperature (800–900 °C), but are not observed for samples annealed at lower temperature (600–700 °C). The luminescence shows a strong correlation with the spacing between As precipitates based on the transmission electron microscope observations. The evolution of luminescence of annealed low‐temperature (LT) GaAs can be reasonably explained by the buried Schottky model. ©1995 American Institute of Physics.