The influence of growth temperature on the nitrogen incorporation into MBE-grown GaInNAs-on-GaAs epilayers

We have studied the influence of growth temperature (within the 410-470 $^{o}$C range) on the nitrogen incorporation into lattice-matched GaInNAs-on-GaAs epilayers grown by molecular-beam epitaxy under constant fluxes. It was found that, over the whole temperature range, nitrogen is incorporated both on substitutional sites and as dimers on Ga and As sites. On substitutional sites nitrogen is present in the form of N-Ga$_{4}$ clusters and, to a lesser extent, in the form of N-Ga$_{3}$In ones. Increasing the growth temperature reduces the amount of substitutional nitrogen and increases the ratio between the N-Ga$_{3}$In and N-Ga$_{4}$ clusters. At the same time, the band gap increases. The amount of nitrogen dimers also decreases with increased growth temperature but the ratio between nitrogen dimers and nitrogen substitutionals appears not to be affected by the growth temperature. The effects of annealing on the incorporated nitrogen are discussed in the paper.