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Mechanisms in the Formation of High Quality Schottky Contacts to n-type ZnO

Published online by Cambridge University Press:  01 February 2011

Martin Ward Allen ,
Holger von Wenckstern ,
Marius Grundmann ,
Stuart Hatfield ,
Paul Jefferson ,
Philip King ,
Timothy Veal ,
Chris McConville  and
Steven Durbin
Martin Ward Allen
Affiliation:
martin.allen@elec.canterbury.ac.nz, University of Canterbury, Electrical and Computer Engineering, 20 Kirkwood Avenue, Ilam, Christchurch, 8043, New Zealand
Holger von Wenckstern
Affiliation:
wenckst@physik.uni-leipzig.de, Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, 04103, Germany
Marius Grundmann
Affiliation:
grundmann@physik.uni-leipzig.de, Universität Leipzig, Institut für Experimentelle Physik II, Leipzig, 04103, Germany
Stuart Hatfield
Affiliation:
Stuart.Hatfield@warwick.ac.uk, University of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
Paul Jefferson
Affiliation:
p.h.jefferson@warwick.ac.uk, University of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
Philip King
Affiliation:
Philip.King@warwick.ac.uk, University of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
Timothy Veal
Affiliation:
timothy.veal@warwick.ac.uk, University of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
Chris McConville
Affiliation:
C.F.McConville@warwick.ac.uk, University of Warwick, Department of Physics, Coventry, CV4 7AL, United Kingdom
Steven Durbin
Affiliation:
steven.durbin@canterbury.ac.nz, University of Canterbury, Electrical and Computer Engineering, Christchurch, 8043, New Zealand
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Abstract

Pt, Ir, Ni, Pd, and silver oxide Schottky contacts were fabricated on the Zn-polar surface of hydrothermally grown bulk ZnO. A relationship was observed between the barrier height of the contact and the free energy of formation of the “metal” oxide. This is consistent with the dominating influence of oxygen vacancies (VO) which tend to pin the ZnO Fermi level close to the VO (+2,0) defect level at approximately EC - 0.7 eV, where EC is the conduction band minimum. Valence band x-ray photoemission spectroscopy and the current - voltage characteristics of planar Schottky diodes, measured on similar Zn-polar surfaces, showed the existence of a vacuum activated surface accumulation layer. This is possibly a consequence of the observed OH termination of the Zn-polar surface. The surface accumulation layer is compensated in atmospheric conditions by the presence of acceptor-like adsorbates, such as O2 and H2O. The formation of high quality Schottky contacts to ZnO should therefore involve the reduction of near surface oxygen vacancies and the removal of H or OH from the surface.

Keywords

II-VIdevicesdefects
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1035: Symposium L – Zinc Oxide and Related Materials–2007 , 2007 , 1035-L10-06
Copyright
Copyright © Materials Research Society 2008

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References

1. Ozgur, U., Alivov, Y.I., Liu, C., Teke, A., Reshchikov, M.A., S, Dogan, Avrutin, V., Cho, S.J., and Morkoc, H., J. Appl. Phys. 98, 041301 (2005).Google Scholar
2. Maeda, K., Sato, M., Niikura, I. and Fukuda, T., Semicond. Sci. Technol. 20, S49 (2005).10.1088/0268-1242/20/4/006Google Scholar
3. Veal, T. D., Jefferson, P. H., Piper, L. F. J., McConville, C. F., Joyce, T. B., Chalker, P. R., Considine, L., Lu, H., and Schaff, W. J., Appl. Phys. Lett. 89, 202110 (2006).Google Scholar
4. Robertson, J., Sharia, O., and Demkov, A.A., Appl. Phys. Lett. 91, 132912 (2007).10.1063/1.2790479Google Scholar
5. Kohan, A. F., Ceder, G., Morgan, D., and C. G. Van de Walle, Phys. Rev. B 61, 15019 (2000).Google Scholar
6. Walle, C. G. Van de, Physica B 308, 899 (2001).10.1016/S0921-4526(01)00830-4Google Scholar
7. Selim, F. A., Weber, M. H., Solodovnikov, D., and Lynn, K. G., Phys. Rev. Lett. 99, 085502 (2007).10.1103/PhysRevLett.99.085502Google Scholar
8. Allen, M. W., Durbin, S. M., and Metson, J. B., Appl. Phys. Lett. 91, 053512 (2007).Google Scholar
9. Schmidt, O., Geis, A., Kiesel, P., Walle, C. G. Van de, Johnson, N. M., Bakin, A., Waag, A., and Dohler, G. H., Superlatt. and Microstruct. 39, 8 (2006).10.1016/j.spmi.2005.08.056Google Scholar
10. Fukutani, K., Iwai, H., Murata, Y., and Yamashita, H., Phys. Rev. B 59, 13020 (1999).10.1103/PhysRevB.59.13020Google Scholar