Dynamic Burstein–Moss shift in GaAs and GaAs/AlGaAs multiple quantum well structures

Time-resolved studies of the dynamic Burstein–Moss shift of the absorption edge following intense photoexcitation are reported for room-temperature samples of GaAs and GaAs/AlGaAs multiple quantum well (MQW) structures. Band-filling times, which correspond to the redistribution of electrons from an energy of 0.5 eV above the bottom of the conduction band to an energy of 0.15 eV, are found to be 1.7 to 1.3 ps for GaAs in the carrier density range of 0.5–2.0×1019 cm−3 and 1 ps for a MQW structure at a density of 2×1019 cm−3. An approximate rate equation model is presented which agrees reasonably well with the experimental results.