Ion irradiation induced nitrogen mobility in a GaInNAs quantum well laser
Changes in the optical properties in GaInNAs/GaAs quantum wells after alpha particle bombardment followed by low temperature annealing are reported. Both blue and red shifts of the lasing wavelength are observed under different annealing conditions. This differs from the usually observed blue shift which is found after high-temperature post-grown annealing. Competing processes that result in the lasing wavelength shifts are energetic considerations which act to increase the number of Ga?N and In?As bonds (maximize the cohesive energy), minimizing the strain of the system which increases the number of In?N and Ga?As bonds (large-ion-small-ion links), maximizing the number of N located at lattice sites effective at shrinking the band-gap and moving the N position within the quantum well. For the case of high-temperature post-grown annealing the increase of Ga?As and In?N bonding wins, resulting in the blue shift observed. The wavelength shifts are discussed in terms of these competing mechanisms.