PICOSECOND CARRIER DYNAMICS AND STUDIES OF AUGER RECOMBINATION PROCESSES IN INDIUM ARSENIDE AT ROOM-TEMPERATURE

Pump-probe midinfrared spectroscopic experiments with 10-ps resolution have been performed in ultrathin (0.09-3.3 mum) undoped molecular-beam epitaxy InAs epilayers on GaAs substrates near and above the fundamental absorption edge (hnu = 0.335-0.485 eV). Significant bleaching due to a dynamic Moss-Burstein effect was seen near the excitation photon frequency. Bleaching recovery times in the range 3000-35 ps were found, and were strongly dependent on the pump photon energy, InAs epilayer thickness, and irradiation dose in the case of layers implanted with high-energy protons. The measured evolution of the excess carrier distributions as a function of delay after excitation allowed the coefficient for Auger recombination in InAs to be measured as 1.1 +/- 0.1 X 10(-26) cm6 s-1. The carrier recombination rates were found to be governed by the Auger effect for "thick" (> 0.5 mum) samples and by a recombination velocity of almost-equal-to 2.7 X 10(4) cm s-1 at the dislocated InAs/GaAs heterointerface for "thin" (< 0.5 mum) samples.