Time-resolved spectroscopy of recombination and relaxation dynamics in InN

Subpicosecond resolution differential transmission measurements of an InN epilayer have been employed to probe the carrier recombination dynamics and hot carrier relaxation processes in these materials at room temperature. We observed a fast initial hot carrier cooling followed by a slower recombination process with characteristic decay times of 300-400 ps. At short times after pulsed excitation, modeling of the observed relaxation suggests that the dominant energy relaxation process is longitudinal optical phonon scattering modified by a strong hot phonon effect. At longer times, a redshift of the peak energy in the differential transmission spectra was observed. This redshift is consistent with a reduction of the bandfilling effect that occurs as the photoexcited carriers recombine. (C) 2003 American Institute of Physics.