Influence of non-radiative recombination on photoluminescence decay time in GaInNAs quantum wells with Ga- and In-rich environments of nitrogen atoms

The influence of non-radiative recombination on the photoluminescence decay time ( _PL) has been studied for GaInNAs/GaAs quantum wells with Ga- and In-rich environments of N atoms. At low temperatures, this influence is suppressed, due to the carrier localization phenomenon, which leads to a spectral dispersion of _PL. For investigated samples, this dispersion has been found to be in the range of 0.2-2.0 ns. With the temperature increase, the free exciton emission starts to dominate instead of the localized exciton emission and the dispersion of _PL disappears. The dynamic of free exciton recombination is strongly influenced by the non-radiative recombination, which varies between samples, due to different concentration of non-radiative centers. The study of influence of non-radiative recombination on _PL has been performed at 180 K, since this temperature is high enough to eliminate the localized emission and activate non-radiative recombination and low enough to observe excitonic emission without strong contribution of free carrier recombination when the sample is excited with low power. It was observed that, for as-grown samples, the _PL increases from 0.14 to 0.25 ns with the change in As/III beam equivalent pressure ratio from 3.8 to 12.1 (in this case, it corresponds to the change in nitrogen nearest-neighbor environment from Ga- to In-rich), whereas, after annealing (i.e., also the change from Ga-rich to In-rich environment of N atoms), this time increases 2-4 times, depending on the As/III ratio. It has been concluded that the _PL is influenced by point defects rather than the nitrogen nearest-neighbor environment, but their concentration is correlated with the type of nitrogen environment.