We report an anomalous temperature dependence of the photoluminescence (PL) spectrum of a 7 nm Ga0.72In0.28N0.028As0.972/GaAs single quantum well. The PL peak energy exhibits an inverted S-shape dependence with temperature. Below 100 K, the PL integrated intensity shows a temperature dependence similar to that of amorphous semiconductors. The observed anomalous behavior is explained by a strong localization of carriers at low temperatures that could be induced by the presence of nitrogen. Thermal annealing does not significantly change the anomalous temperature dependence.

We report on the effect of rapid thermal annealing (RTA) on the photoluminescence (PL) properties of GaNxAs1−x/GaAs structures. In particular, a blueshift of the PL peak energy is observed when annealing the samples. The results are examined as a consequence of a RTA-induced nitrogen diffusion inside the GaNxAs1−x material rather than diffusion out of the alloy, which homogenizes initial nitrogen composition fluctuations. We propose a simple model that describes the RTA-induced blueshift of the low temperature PL peak energy. This model is in good agreement with experimental results and is consistent with recent studies in which lateral composition fluctuations in the GaNAs alloy were reported.

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