Temperature dependence of near ultraviolet photoluminescence in ZnO/(Mg, Zn)O multiple quantum wells

• Main Authors: Makino, T., Tuan, N. T., Sun, Handong, Chia, C. H., Segawa, Y., Kawasaki, M., Ohtomo, A., Tamura, K., Koinuma, H.
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2009
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: https://hdl.handle.net/10356/104086; http://hdl.handle.net/10220/6135; http://scitation.aip.org.ezlibproxy1.ntu.edu.sg/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000078000014001979000001
• Institution: Nanyang Technological University

We report on temperature dependence of excitonic photoluminescence (PL) from ZnO/(Mg, Zn)O multiple quantum wells (MQWs). Two kinds of MQWs having different barrier heights grown by laser molecular-beam epitaxy showed significantly different temperature dependences of PL spectra; in ZnO/Mg0.27Zn0.73O MQWs, the PL peak energy at 50–200 K was a monotonically increasing function of temperature, which was opposite to that ascribed by band gap shrinkage. Moreover, spectra taken at 95–200 K encompassed two peaks, both of which originated from recombination of localized excitons. The temperature-induced shift (redshift-blueshift-peak duplication-redshift) At 5–300 K is caused by a change in the exciton dynamics with increasing temperature due to inhomogeneity and the exciton localization effect. On the other hand, the corresponding dependence in ZnO/Mg0.12Zn0.88O MQWs (lower barrier height) was similar to that in bulk II–VI semiconductors.