Abstract

Femtosecond spectroscopy has been extensively exploited to analyze elementary carrier interactions in semiconductors. Most measurements to date have been performed under conditions such that electron dynamics dominate the transient response; little is known about hole-relaxation dynamics in direct-gap semiconductors. By using time-resolved luminescence this problem has recently been addressed in n-doped GaAs, in which the high-density electron plasma introduced by doping constitutes an important thermal bath for the nonequilibrium holes.^1-3 We show, for the first time to our knowledge, that by using proper excitation and probing conditions, the heavy-hole (hh) thermalization dynamics can be selectively analyzed in intrinsic bulk GaAs by using two-wavelength femtosecond absorption-saturation spectroscopy.

© 1995 Optical Society of America