Temperature-dependent photoluminescence measurements on a sub-micrometer length scale on green light emitting InGaN/GaN quantum wells

Abstract

For an InGaN/GaN multiquantum well sample with low threading dislocation density (TDD), temperature-dependent microphotoluminescence measurements were performed. Evaluation of the behavior of the photoluminescence peak energy leads to the conclusion that even at a length scale of about 500 nm we still see the same S-shape of the temperature-dependent energy shift that was observed on a far larger scale. The behavior of the temperature-dependent full width at half maximum of the spectra and the integrated intensity leads to similar conclusions. We therefore demonstrate that the phenomenon responsible for the S-shape acts on a length scale that is far smaller than 500 nm. In addition, the behavior of the integrated intensity shows a fluctuation of local point defect density in the analyzed sample with its low TDD.