The mechanism of radiative recombination in light-emitting devices composed on InGaN quantum wells

By means of time-resolved emission spectroscopy, the emission dynamics of InGaN quantum well light-emitting devices is evaluated. The localization, radiation, and nonradiating recombination processes of the exciton are evaluated. It is found that there exist random potential fluctuations in the quantum well in samples with less than about 10% In in the InGaN activation layer. By means of these fluctuations, localization of the excitons can be attained. It is also found that the degree of localization increases as the In composition is increased, and that quantum dot-like regions are naturally formed in samples with an In content of more than about 20%. It is found that the capture of excitons by nonradiating recombination centers is suppressed and that a high-emission quantum efficiency is realized by such a pronounced localization. (C) 1998 Scripta Technica.