Emission-state transition in InGaAsSb/AlGaAsSb multiple quantum wells induced by rapid thermal annealing

InGaAsSb/AlGaAsSb multiple quantum wells (MQWs) hold significant potential for mid-infrared optoelectronics. However, their optical and structural behavior at high temperatures remains complex and necessitates further investigation. To address this, the MQWs were subjected to rapid thermal annealing (RTA) at various temperatures for 40 s. The impact of annealing temperature on the structural and compositional properties of InGaAsSb/AlGaAsSb MQWs was assessed by Raman spectrum, high-resolution transmission electron microscopy (HRTEM) with energy-dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), and X-ray diffraction (XRD) analyses. Higher annealing temperatures induced compositional segregation, disrupting the structure of InGaAsSb/AlGaAsSb MQWs. Temperature- and power-dependent photoluminescence (PL) spectra revealed exciton emission state transitions and non-radiative recombination, highlighting the evolution of the P3 emission peak from free exciton (unannealed) to localized exciton (RTA@400 °C) and back to free exciton (RTA@600 °C). This study lays a foundation for advancing the understanding and optimization of MQWs, offering valuable insights applicable to complex systems with similar MQW architectures.