Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 36: Poster Ib
HL 36.3: Poster
Dienstag, 8. März 2016, 15:00–19:00, Poster A
On the E3 deep-level in ZnO crystals — Rainer Pickenhain1, Matthias Schmidt2, •Holger von Wenckstern1, and Marius Grundmann1 — 1Universität Leipzig, Institut für Experimentelle Physik II, Abteilung Halbleiterphysik, Linnéstraße 5, 04103 Leipzig — 2Helmholtz-Zentrum für Umweltforschung GmbH, Abteilung Isotopenbiogeochemie, Permoserstraße 15, 04318 Leipzig
The deep-level E3 is frequently detected in n-doped ZnO crystals. Its thermal activation energy for electron emission into the conduction band amounts to approximately 280meV determined by deep-level transient spectroscopy (DLTS). In this work ZnO crystals from different sources were investigated by various space charge spectroscopic techniques with additional optical excitation. In the experiments the parameters temperature 4 K<T<350 K, photon energy 0.25 eV<hν<4 eV and DLTS rate window 10−3 Hz<r<104 Hz were varied. The photo-ionisation cross-sections of two optical emission processes of electrons bound by E3 into the conduction band were measured. The results of these experiments suggest E3 to be a double centre with negative-U properties. Such model also explains the observed optical transitions. Based on the findings in this study a model for the E3 level is suggested. The model is discussed in the context of previously published theoretical work on native defects in ZnO.