Optical investigation of strong exciton localization in high Al composition AlxGa1-xN alloys.

ABSTRACT

The exciton localization in wurtzite AlxGa1-xN alloys with x varying from 0.41 to 0.63 has been studied by deep-ultraviolet photoluminescence (PL) spectroscopy and picosecond time-resolved PL spectroscopy. Obvious S-shape temperature dependence was observed indicating that the strong exciton localization can be formed in high Al composition AlxGa1-xN alloys. It was also found that the Al composition dependence of exciton localization energy of AlGaN alloys is inconsistent with that of the excitonic linewidth. We contribute the inconsistency to the strong zero-dimensional exciton localization.