Positron annihilation lifetime spectroscopy of ZnO bulk samples

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© 2007 American Physical Society (APS). This is the accepted version of the following article: Zubiaga, A. & Plazaola, F. & Garcia, J. A. & Tuomisto, Filip & Munoz-Sanjose, V. & Tena-Zaera, R. 2007. Positron annihilation lifetime spectroscopy of ZnO bulk samples. Physical Review B. Volume 76, Issue 8. 085202/1-8. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.76.085202, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.76.085202.

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2007

Major/Subject

Mcode

Degree programme

Language

en

Pages

085202/1-8

Series

Physical Review B, Volume 76, Issue 8

Abstract

In order to gain a further insight into the knowledge of point defects of ZnO, positron annihilation lifetime spectroscopy was performed on bulk samples annealed under different atmospheres. The samples were characterized at temperatures ranging from 10 to 500 K. Due to difficulties in the conventional fitting of the lifetime spectra caused by the low intensity of the defect signals, we have used an alternative method as a solution to overcome these difficulties and resolve all the lifetime components present in the spectra. Two different vacancy-type defects are identified in the samples: Zn vacancy complexes (VZn−X) and vacancy clusters consisting of up to five missing Zn-O pairs. In addition to the vacancies, we observe negative-ion-type defects, which are tentatively attributed to intrinsic defects in the Zn sublattice. The effect of the annealing on the observed defects is discussed. The concentrations of the VZn−X complexes and negative-ion-type defects are in the 0.2–2 ppm range, while the cluster concentrations are 1–2 orders of magnitude lower.

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Keywords

ZnO, bulk, positron annihilation

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Citation

Zubiaga, A. & Plazaola, F. & Garcia, J. A. & Tuomisto, Filip & Munoz-Sanjose, V. & Tena-Zaera, R. 2007. Positron annihilation lifetime spectroscopy of ZnO bulk samples. Physical Review B. Volume 76, Issue 8. 085202/1-8. ISSN 1098-0121 (printed). DOI: 10.1103/physrevb.76.085202