Thermal quenching of photoluminescence in Ga(AsBi)

We report on a comparative experimental and theoretical study of the thermal quenching of the photoluminescence (PL) intensity in Ga(AsBi)/GaAs heterostructures. An anomalous plateau in the PL thermal quenching is observed at intermediate temperatures under relatively low excitation intensities. Theoretical analysis based on a well-approved approach shows that this peculiar behavior points at a non-monotonous density of states (DOS) in the disorder-induced band tails with at least two-energy-scales. While in previous studies carried out at relatively high excitation intensities a single-energy-scale was sufficient to fit the thermal quenching of the PL in Ga(AsBi), our study at lower excitation intensities proves that two-energy-scales of disorder contribute to the thermal quenching of the PL. Possible energy shapes of the DOS, which can fit experimental data, are revealed.