Nitrogen ions were implanted into indirect‐gap AlxGa1−xAs (x=0.53) and photoluminescence measurements were made at 2 °K as a function of annealing temperature. After sufficient annealing three emission bands were observed presumably due to the substitution of the nitrogen atoms with the host As atoms and the integrated intensity of the luminescence of the wafer increased by about 200 times compared with that of the unimplanted and annealed wafer. This can probably be ascribed to the formation of isoelectronic traps in the AlxGa1−xAs : N system.