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Optical Properties of Excitons in ZnO-based Quantum Well Heterostructures

T. Makino·Y. Segawa·M. Kawasaki·H. Koinuma
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Abstract

Recently the developments in the field of II-VI-oxides have been spectacular. Various epitaxial methods has been used to grow epitaxial ZnO layers. Not only epilayers but also sufficiently good-quality multiple quantum wells (MQWs) have also been grown by laser molecular-beam epitaxy (laser-MBE). We discuss mainly the experimental aspect of the optical properties of excitons in ZnO-based MQW heterostructures. Systematic temperature-dependent studies of optical absorption and photoluminescence in these MQWs were used to evaluate the well-width dependence and the composition dependence of the major excitonic properties. Based on these data, the localization of excitons, the influence of exciton-phonon interaction, and quantum-confined Stark effects are discussed. The optical spectra of dense excitonic systems are shown to be determined mainly by the interaction process between excitons and biexcitons. The high-density excitonic effects play a role for the observation of room-temperature stimulated emission in the ZnO MQWs. The binding energies of exciton and biexciton are enhanced from the bulk values, as a result of quantum-confinement effects.

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T. Makino, Y. Segawa, M. Kawasaki, H. Koinuma. 2004-10-10. Optical Properties of Excitons in ZnO-based Quantum Well Heterostructures. https://doi.org/10.1088/0268-1242%2F20%2F4%2F010

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