Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1543813 | Physica E: Low-dimensional Systems and Nanostructures | 2016 | 5 Pages |
Abstract
Photoluminescence (PL) properties of two different InGaN/GaN multiple quantum well (MQW) structures, without and with an InGaN/GaN quasi-superlattice (QSL) underlying buffer layer, were investigated. The results show that inserting a QSL between the n-GaN and MQWs can release the strain in the MQW region, since the sample with a QSL shows a smaller excitation power-dependent blue-shift of its peak energy than that without. Meanwhile, inserting a QSL enhances the localization effect of the carriers inferred from an unusual red-shift of the peak energy with increasing excitation power in low excitation range, and from a more obvious “S-shaped” temperature-dependent behavior of the peak energy characteristic: the strain release facilitates the slight composition fluctuation or phase separation of the InGaN well layers. The reduction of the quantum-confined Stark effect and enhancement of the localization effect of the MQWs induced by the strain release, greatly enhance the radiative recombination rate of the MQWs.
Related Topics
Physical Sciences and Engineering
Materials Science
Electronic, Optical and Magnetic Materials
Authors
Qi Mu, Mingsheng Xu, Xuesong Wang, Qiang Wang, Yuanjie Lv, Zhihong Feng, Xiangang Xu, Ziwu Ji,