Picosecond time-resolved study of excitons in GaAs-A1As multi-quantum-well structures

Energy- and time-resolved measurements of luminescence of $1s$ excitons ($n=1,e-hh$) in GaAs-A1As multi-quantum-well structures have been carried out for the first time in the picosecond time domain. Dynamical population changes of excitons are directly visualized in the energy-time coordinates. Results indicate that excitons lose their energy in the exciton band at a rate of 1.0×${10}^6$ eV/s. This rate is much slower than the calculated kinetic-energy-loss rate and is ascribed to the random nature of the well.