Reduction of band-gap energy in GaNAs and AlGaNAs synthesized by N+ implantation

We have studied the optical properties of nitrogen implanted GaAs and AlGaAs samples. The fundamental band-gap energy has been found to decrease with the increasing N+ implantation dose in a manner similar to that commonly observed in GaNAs and GaInNAs alloys grown by molecular beam epitaxy or metal organic chemical vapor deposition. Our results indicate that GaNxAs1-x and AlxGa1-xNyAs1-y alloys can be formed by implantation of nitrogen followed by appropriate postimplantation annealing treatments. As inferred from the magnitude of the band gap shift, the percentage of the implanted N atoms incorporated on the substitutional As sites is estimated to be around 12%. (C) 1999 American Institute of Physics. [S0003-6951(99)00336-8].