Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Exciton binding energies in wurtzite ZnO/MgZnO quantum wells
The exciton binding energies of ZnO/MgZnO quantum well (QW) structures were investigated by considering piezoelectric (PZ) and spontaneous (SP) polarizations. These results are compared with those of GaN/AlGaN QW lasers. With increasing sheet carrier density, both QW structures show that the exciton binding energy is significantly reduced, suggesting that excitons are nearly bleached at typical densities ( approximately 1013cm−2 ) for which lasing occurs. The flat-band model of the both QW structure shows that, with decreasing well width, the exciton binding energy increases due to the increasing confinement effect in the well. However, the self-consistent model of both QW structures shows that, with the inclusion of the internal field, the exciton binding energy is substantially reduced compared to that of the flat-band value. This is resulted from the smaller overlap due to spatial separation between the conduction and the valence wave functions as the well width gets larger. We also know that the exciton binding energy of ZnO/MgZnO QW structures is much larger than that of GaN/AlGaN QW structures. The larger exciton binding energy observed in ZnO/MgZnO QW structure can be explained by the larger matrix element than the GaN/AlGaN QW stucture, in addition to its smaller dielectric constant.
Exciton binding energies in wurtzite ZnO/MgZnO quantum wells
The exciton binding energies of ZnO/MgZnO quantum well (QW) structures were investigated by considering piezoelectric (PZ) and spontaneous (SP) polarizations. These results are compared with those of GaN/AlGaN QW lasers. With increasing sheet carrier density, both QW structures show that the exciton binding energy is significantly reduced, suggesting that excitons are nearly bleached at typical densities ( approximately 1013cm−2 ) for which lasing occurs. The flat-band model of the both QW structure shows that, with decreasing well width, the exciton binding energy increases due to the increasing confinement effect in the well. However, the self-consistent model of both QW structures shows that, with the inclusion of the internal field, the exciton binding energy is substantially reduced compared to that of the flat-band value. This is resulted from the smaller overlap due to spatial separation between the conduction and the valence wave functions as the well width gets larger. We also know that the exciton binding energy of ZnO/MgZnO QW structures is much larger than that of GaN/AlGaN QW structures. The larger exciton binding energy observed in ZnO/MgZnO QW structure can be explained by the larger matrix element than the GaN/AlGaN QW stucture, in addition to its smaller dielectric constant.
Exciton binding energies in wurtzite ZnO/MgZnO quantum wells
J. S. Hong, (Autor:in) / S. W. Ryu, (Autor:in) / W. P. Hong, (Autor:in) / J. J. Kim, (Autor:in) / H. M. Kim, (Autor:in) / Park, S. H. (Autor:in)
01.10.2006
359285 byte
Aufsatz (Konferenz)
Elektronische Ressource
Englisch
Exciton Localization in ZnSe-Based Quantum Wells
| British Library Online Contents | 1995
Non-Linear Exciton Spectroscopy of GaN/AlGaN Quantum Wells
| British Library Online Contents | 1998
Exciton Magnetic Polarons in Semimagnetic Quantum Wells with Nonmagnetic Barriers
| British Library Online Contents | 1995
| British Library Online Contents | 1993
Linear spectroscopy and exciton binding energies in (Zn, Cd)Se ZnSe heterostructures
| British Library Online Contents | 1997