Optical characterization and carriers transfer between localized and delocalized states in Si-doped GaAsN/GaAs epilayer

摘要

The optical properties and recombination processes, in low nitrogen content GaAsN/GaAs structure, are studied by continuous wave photoluminescence (cw PL) and time resolved photoluminescence (TRPL) versus temperature. It is found that the decay process strongly depends on the sample temperature. We showed that there are three temperature domains. For temperature lower than 40 K, the decay time is about 2000 ps and the recombination process is purely radiative. Between 40 K and 80 K, there is a competition between radiative and non radiative processes and the decay time is very sensitive to the temperature variation. For temperatures higher than 80 K the decay time is found to be close to 1000 ps and the carriers' recombination is dominated by the non radiative process via the localized states. The photocarrier transfer between localized and delocalized states is observed on the associated delay spectra and it is found to be 800 ps. (C) 2015 Elsevier B.V. All rights reserved.