Abstract
Crystal orientation effects on electronic and optical properties of ZnO/MgZnO QW structures are investigated by taking into account the non-Markovian gain model with many-body effects. These results are compared with those for GaN-based QW structures. In a range of small crystal angles, ZnO/MgZnO QW structures have a lower internal field than GaN/AlGaN and InGaN/GaN QW structures. However, ZnO/MgZnO QW structures show a larger internal field than GaN-based QW structures at crystal angles near θ =50°. The WZ ZnO/MgZnO QW structures are shown to have much larger optical gain than the GaN-based QW structures for small crystal angles. This is because WZ ZnO/MgZnO QW structures have larger matrix element and smaller effective masses than InGaN/GaN QW structures near the (0001) crystal orientation. On the other hand, in the case of the (101̄0) crystal orientation, the optical gain of ZnO/MgZnO QW structures becomes smaller than that of InGaN/GaN QW structures due to the increase of the effective mass. In addition, the ZnO/MgZnO QW structures have a maximum in the optical gain near θ =50°, which can be explained by the fact that the average hole effective mass increases although the matrix element at high carrier density is improved with increasing crystal angle.
Original language | English |
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Pages (from-to) | 935-952 |
Number of pages | 18 |
Journal | Optical and Quantum Electronics |
Volume | 38 |
Issue number | 12-14 |
DOIs | |
State | Published - Sep 2006 |
Keywords
- AlGaN
- Crystal orientation
- GaN
- Laser
- MgZnO
- Optical gain
- Quantum well
- ZnO
- ZnO/MgZnO