Abstract

Hot carrier distributions in GaAs multiple quantum-well structures (MQWS) have been excited, and cooling of the resulting thermatized plasma to the lattice temperature has been monitored.¹ In the experiments reported here we excite a non-equilibrium carrier population in such a short time that the temperature of the distribution cannot yet be defined. Using femtosecond spectroscopic techniques we are able to show that the initially excited nonthermal carrier distribution evolves to a thermalized distribution within 200 fs. By monitoring time development of the bleaching of the excitan resonance we determine for the first time the relative effectiveness of Coulomb screening and Pauli exclusion on quasi 2-D exciton absorption.

© 1986 Optical Society of America