Carrier localization effect on luminescence spectra of IIIV heterostructures

A steady-state rate-equation model for temperature-dependent luminescence spectra from localized-state material system is presented. The effects of thermal emission, recapturing, radiative and nonradiative recombination are taken into account in the model. Two localized-state material systems, including InAs/GaAs quantum-dot and InGaN/GaN-multi-quantum-well samples were prepared. It is found that the temperature-dependent behaviors of luminescence emission energy obtained from the two samples are quite different. In the mid-temperature range, the emission peaks exhibit a redshift for quantum-dot sample, but a blueshift for multi-quantum-well sample. The peak energies of the luminescence spectra are simulated in this model and show a good agreement with experiment. The corresponding luminescence mechanisms of carriers in localized-state material systems, which lead to the diversity are quantitatively discussed in detail by the model.