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- Title
Free and bound excitonic effects in Al<sub>0.5</sub>Ga<sub>0.5</sub>N/Al<sub>0.35</sub>Ga<sub>0.65</sub>N MQWs with different Si-doping levels in the well layers.
- Authors
He, Chenguang; Qin, Zhixin; Xu, Fujun; Hou, Mengjun; Zhang, Shan; Zhang, Lisheng; Wang, Xinqiang; Ge, Weikun; Shen, Bo
- Abstract
Free exciton (FX) and bound exciton (BX) in Al0.5Ga0.5N/Al0.35Ga0.65N multiple quantum wells (MQWs) with different Si-doping levels in the well layers are investigated by photoluminescence (PL) spectra. Low temperature (10 K) PL spectra identify a large binding energy of 87.4 meV for the BX in undoped sample, and 63.6 meV for the BX in Si-doped (2 × 1018 cm−3) sample. They are attributed to O-bound and Si-bound excitons, respectively. The large binding energies of BX are assumed to originate from the strong quantum confinement in the quantum wells, which also leads to a stronger FX PL peak intensity in comparison with BX at 10 K. Si-doping is found to suppress the FX quenching by reducing threading dislocation density (TDD) in the well layers, leading to a significant improvement of IQE from 33.7% to 45%.
- Subjects
EXCITON theory; QUANTUM wells; DOPING agents (Chemistry); BINDING energy; PHOTOLUMINESCENCE
- Publication
Scientific Reports, 2015, p13046
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/srep13046