Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 30: II-VI Halbleiter III
HL 30.1: Vortrag
Samstag, 5. März 2005, 15:00–15:15, TU P164
Characterisation of vapor transport grown ZnO bulk crystals — •Detlev M. Hofmann1, Joachim Sann1, Daniel Pfisterer1, Angelika Polity1, Valentin Laguta1, Albrecht Hofstaetter1, Bruno K. Meyer1, Thomas Frank2, Gerhard Pensl2, R. Tena-Zaera3, J. Zuninga-Perez3, and Vincente Munioz Sanjose3 — 1I. Physikalisches Institut, Justus-Liebig-Universität, Heinrich-Buff-Ring 16, 35392 Giessen, Germany — 2Institut für angewandte Physik, Universität Erlangen-Nürnberg, Staudtstr. 7, Gebäude A3, 91058 Erlangen, Germany — 3Dpto. Fisica Aplicada y Electromagnetismo, co. Dr. Moliner n∘50, 46100 Burjassot Valencia, Spain
The samples were as grown, or treated in post growth annealing experiments at temperatures between 900∘C and 1200∘C in vacuum, O2 or Zn atmospheres. Samples annealed in Zn atmosphere are redish and become transparent after O2 annealing. In luminescence experiments we find deep emission bands related to the oxygen vacancies and to residual copper, in the excitonic range several donor bound excitons are observed. The energy positions of the excitons are similar to the H-related and the Al-related donor bound excitons and that of I7. The presence of residual donors is confirmed by EPR and ENDOR. DLTS shows that the traps commonly labeled E3 (ECB - 430 meV) and E4 (ECB - 530 meV) are in the material and that E4 increases after the Zn anneal. The results are used to construct a level scheme of the centers in the material in order to explain the optical and electrical properties. This work was financially supported by the EU-SOXESS-network.