Exciton localization in (In,Ga)N/GaN single quantum well structures.

The authors have performed a detailed investigation of the low temp. (T = 6 K) photoluminescence spectra and recombination lifetimes of localized excitons in a set of (In,Ga)N/GaN single quantum wells in which the indium fraction in the quantum well was varied. They found that with increasing indium fraction the photoluminescence peak emission moved to lower energy and the intensities of the phonon replicas relative to the zero-phonon line increased. From a multi-Gaussian fit of the exptl. data, the authors extd. the Huang-Rhys factor (S), a measure of the strength of the exciton coupling with LO-phonons. By comparing exptl. S factors with the results of a theor. model, they found that the excitons localize on a length scale of .apprx.2 nm in their samples. [on SciFinder (R)]