On the interplay of point defects and Cd in non-polar ZnCdO films

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© 2013 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the authors and the American Institute of Physics. The following article appeared in Journal of Applied Physics, Volume 113, Issue 2 and may be found at http://scitation.aip.org/content/aip/journal/jap/113/2/10.1063/1.4775396.

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Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2013

Major/Subject

Mcode

Degree programme

Language

en

Pages

023512/1-7

Series

Journal of Applied Physics, Volume 113, Issue 2

Abstract

Non-polar ZnCdO films, grown over m- and r-sapphire with a Cd concentration ranging between 0.8% and 5%, have been studied by means of slow positron annihilation spectroscopy (PAS) combined with chemical depth profiling by secondary ion mass spectroscopy and Rutherford back-scattering. Vacancy clusters and Zn vacancies with concentrations up to 10exp17 cm−3 and 10exp18 cm−3, respectively, have been measured inside the films. Secondary ion mass spectroscopy results show that most Cd stays inside the ZnCdO film but the diffused atoms can penetrate up to 1.3 μm inside the ZnO buffer. PAS results give an insight to the structure of the meta-stable ZnCdO above the thermodynamical solubility limit of 2%. A correlation between the concentration of vacancy clusters and Cd has been measured. The concentration of Zn vacancies is one order of magnitude larger than in as-grown non-polar ZnO films and the vacancy cluster are, at least partly, created by the aggregation of smaller Zn vacancy related defects. The Zn vacancy related defects and the vacancy clusters accumulate around the Cd atoms as a way to release the strain induced by the substitutional CdZn in the ZnO crystal.

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Keywords

ZnCdO, point defects, positron annihilation spectroscopy, secondary ion mass spectrometry

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Citation

Zubiaga, A. & Reurings, F. & Tuomisto, Filip & Plazaola, F. & Garcia, J. A. & Kuznetsov, A. Yu. & Egger, W. & Zuniga-Perez, J. & Munoz-Sanjose, V. 2013. On the interplay of point defects and Cd in non-polar ZnCdO films. Journal of Applied Physics. Volume 113, Issue 2. 023512/1-7. ISSN 0021-8979 (printed). DOI: 10.1063/1.4775396