Abstract

Many of the optical and electronic properties of semiconductor heterostructures depend on the dynamics of electronic excitations. Disorder due to nonideal growth conditions can modify these properties and allow new dynamical processes not present in an ideal crystal. One such process is carrier localisation on an atomic scale. Indeed, measurements have shown the presence of exciton localization,¹ the presence of a mobility edge,² and that low-temperature excitonic relaxation proceeds via phonon-assisted migration between localization sites.³ Using resonant picosecond four-wave-mixing (FWM) laser spectroscopy, we probe the complex nature of disorder-induced effects near the band edge of GaAs/AlGaAs multiple quantum well (MQW) structures at low temperature.

© 1992 Optical Society of America