Effects of nitrogen incorporation and thermal annealing on the optical and spin properties of GaPN dilute nitride alloys

Here, we report on the structural, optical and magneto-optical properties of as-grown and thermal annealed GaPN thin films containing different N concentrations grown by Solid-Source Molecular Beam Epitaxy on GaP substrates. A wide range of characterization techniques were used to investigate the effect of N incorporation and thermal annealing effect of GaPN/GaP epilayers for a N content between 0.5% and 3%. Our results have shown that as we increase the N content the PL peak energy presents a red shift which is explained by a band gap reduction. However, important effects of exciton localization on optical properties were also evidenced from cw and time resolved PL (PLRT) and magneto-PL. Our results have demonstrated that as the concentration of N is increased, exciton localization effect is enhanced. A substantial improvement of the optical quality and spin properties of the epilayers has been observed after thermal annealing which are significantly more important for samples with higher nitrogen contents. •Comprehensive characterization of the structural and optical properties of GaPN.•Investigation of the synthesis and physical properties of dilute nitrides.•Study of alloys which have great potential for the development of high efficiency solar cells.