Ligth induced bleaching and absorption kinetics in highly excited InN layers

Abstract

We study the carrier recombination in highly excited InN epilayers by means of femtosecond differential transmission technique. The light induced bleaching or absorption is observed by tuning the probe photon energy by 100‐200 meV above or below the bandgap. The induced absorption decays roughly twice faster than the induced bleaching at the absorption edge. We conclude that the induced absorption kinetics show dynamics of the overall excess carrier population, while the bleaching at the absorption edge is related to carrier recombination in the band tails. Lifetime τ of absorption decay is inversely dependent on the total electron density τ=B*·(n0+N) with B*=4×10–10 cm3/s, which agrees well with the results of previous measurements. High B* value cannot be attributed to band‐to‐band recombination and supports the assumption that defect‐assisted Auger is the dominant nonlinear recombination process in InN. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)