Time-resolved absorption studies of the ZnSe/ZnSTe superlattice

The time-resolved differential absorption of the ZnSe/ZnSTe superlattice is studied using femtosecond pump-probe measurements. Transient spectral hole burning due to the initial nonthermal carrier distribution is observed at zero time delay and the carriers an thermalized within 0.5 ps. The high-ene rgy tail of the differential absorption spectra was used to deduce the effe ctive temperature of the thermalized carriers. Rapid hot-carrier cooling fr om a temperature of 763 to 450 K within the first 4 ps is observed, with ca rrier cooling slowing dawn hence. This initial fast hot-carrier cooling is consistent with the strong carrier-phonon interaction in large gap II-VT se miconductors. (C) 2001 Academic Press.