Time resolved PL study of GaInNAs quantum wells

Time resolved photoluminescence (PL) has been used to investigate the low-temperature emission kinetics of GaInNAs and InGaAs quantum wells (QWs). The emission from InGaAs QWs remains stable over time; in contrast a clear red-shift of up to 20 meV is observed in the GaInNAs emission peak over a time period of 200-300 ps. This red-shift is interpreted in terms of trapping of excited carriers into localised excitonic states within the GaInNAs material. The presence of localised tail states is further supported by steady-state PL measurements; at low temperatures, a low-energy tail appears and a characteristic S-shape temperature dependence is observed in the emission energy.