Thermal redistribution of localized excitons and its effect on the luminescence band in InGaN ternary alloys

Temperature-dependent photoluminescence measurements have been carried out in zinc-blende InGaN epilayers grown on GaAs substrates by metalorganic vap or-phase epitaxy. An anomalous temperature dependence of the peak position of the luminescence band was observed. Considering thermal activation and t he transfer of excitons localized at different potential minima, we employe d a model to explain the observed behavior. A good agreement between the th eory and the experiment is achieved. At high temperatures, the model can be approximated to the band-tail-state emission model proposed by Eliseev et al. [Appl. Phys. Lett. 71, 569 (1997)]. (C) 2001 American Institute of Phys ics.