Stimulated emission induced by exciton–exciton scattering in ZnO/ZnMgO multiquantum wells up to room temperature

• Main Authors: Sun, Handong, Makino, T., Tuan, N. T., Segawa, Y., Tang, Z. K., Wong, G. K. L., 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
• Online Access: https://hdl.handle.net/10356/101294; http://hdl.handle.net/10220/6154; http://scitation.aip.org.ezlibproxy1.ntu.edu.sg/getabs/servlet/GetabsServlet?prog=normal&id=APPLAB000077000026004250000001
• Institution: Nanyang Technological University

The mechanism of ultraviolet stimulated emission was investigated in ZnO/ZnMgO multiquantum wells. Stimulated emission induced by exciton–exciton scattering occurred throughout a range of temperatures from 5 K to room temperature. At temperatures higher than 160 K, stimulated emission due to electron-hole plasma recombination was also observed with a higher excitation threshold than that of exciton–exciton scattering. The exciton binding energies of multiquantum wells were larger than that of bulk ZnO and increased with a decrease in the well widths. This enhancement of exciton binding energy is due to the quantum-confinement effect and is favorable for the stability of exciton states.