Microscopic Luminescence Properties of ZnO and ZnO Based Heterostructures
F. Bertram and J. Christen
Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, Postbox 4120, 39106 Magdeburg, Germany
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Received: 17 06 2006;
The optical properties of excitonic recombinations in ZnO are investigated by spatially and spectrally resolved cathodoluminescence measurements. The relevance of cathodoluminescence microscopy as a spatially resolved luminescence technique as a simple but very powerful characterization method is stressed out in discussions of a wide variety of appropriate examples. A thorough discussion of the various features of the cathodoluminescence of an undoped ZnO bulk crystal, epitaxially grown ZnO and MgZnO/ZnO/MgZnO quantum well structure is given. Particular attention is devoted to the impact of the internal electrical fields, e.g. the Franz-Keldysh effect in ZnO. Furthermore, this study focuses on the spectral variations as a function of depth to the interface in ZnO homo- and heterostructures. Our aim is to establish the nature of the optical transitions influenced by internal fields, defects and impurity doping in ZnO/GaN and ZnO/ZnO interfaces. This review covers also the vertical transport, diffusion and capture of carriers in a MgZnO/ZnO/MgZnO quantum well structure.
DOI: 10.12693/APhysPolA.110.103
PACS numbers: 78.60.Hk, 78.66.Hf, 81.05.Dz, 81.15.Gh