FEMTOSECOND TWO-PHOTON INDUCED LUMINESCENCE SPECTROSCOPIC STUDY OF CARRIER THERMALIZATION AND THE LIFETIME OF SPLIT-OFF HOLES IN GaAs

Abstract

Time-resolved two-photon induced luminescence spectroscopy is used to study the relaxation dynamics of holes in GaAs following valence-to-conduction band femtosecond pulse excitation in the near-infrared and heavy- and light-hole to split-off resonant transitions in the mid-infrared. It is shown that there is a rapid change in the electron and hole temperatures due to thermalization of the carrier distributions in the valence and conduction bands and that the collisions between the electrons and heavy holes are not elastic when scattering to the light hole band is possible. The lifetime of the split-off holes near the zone center is within the limits of 40 to 80 femtoseconds at room temperature.