Abstract

The dynamics of carrier-carrier scattering in GaAs multiple quantum well structures have been effectively isolated from other competing relaxation mechanisms such as phonon emission and intervalley scattering in previous experiments utilizing femtosecond optical excitation near the band edge. Thermalization times of ~100 fs were obtained in these experiments in undoped quantum wells at excitation density of ~2 × 10¹⁰ cm^-2.¹ Modulation-doped semiconductor materials are of great scientific and technological importance. By doping the barrier layers of multiple quantum well structures with impurities, large densities of excess electrons or excess holes can be introduced to the wells without adding direct impurity scattering. These advances have resulted in high-mobility transistors and the demonstration of ballistic transport in GaAs devices.²

© 1988 Optical Society of America