Hostname: page-component-cd9895bd7-jn8rn Total loading time: 0 Render date: 2024-12-27T02:10:40.512Z Has data issue: false hasContentIssue false
  • English
  • Français

New method of reducing threading dislocation in epitaxial ZnO films grown on c-sapphire

Published online by Cambridge University Press:  01 February 2011

Yuekui Sun  and
David Cherns
Yuekui Sun
Affiliation:
[email protected], University of Bristol, Department of Physics, H.H.Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom, 00441179288750, 00441179255624
David Cherns
Affiliation:
[email protected], University of Bristol, Department of Physics, H.H.Wills Physics Laboratory,, University of Bristol,, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
Get access

Abstract

The behavior of threading dislocations (TDs) in ZnO/(0001)sapphire heterostructures grown by a two-step method have been investigated. The initial template, grown by pulsed laser deposition, consisted of a continuous underlayer, which was O-polar and an overlayer comprising a high density of Zn-polar nanorods. High densities (∼7×1010 cm−2) of TDs were found to be restricted to the underlayer, whereas the nanorods were almost defect-free. Subsequent treatments by either hydrothermal growth or chemical vapour deposition (CVD) achieved epitaxial lateral overgrowth of nanorods and led to continuous Zn-polar films. The low TD density of nanorods remained until misoriented grain boundaries and boundary dislocations were generated when neighbouring nanorods become coalesced. The lateral migration of TDs in the overgrowth led to dislocation interactions and reduction of TDs. The total TD density at the top of the overlayer was estimated to be ∼1×109 cm−2 for hydrothermal growth and ∼7×109 cm−2 for CVD growth.

Keywords

epitaxydislocationstransmission electron microscopy (TEM)
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1035: Symposium L – Zinc Oxide and Related Materials–2007 , 2007 , 1035-L09-07
Copyright
Copyright © Materials Research Society 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Ozgur, U. et al. J. Appl. Phys. 98, 041301 (2005)10.1063/1.1992666Google Scholar
2. Kwon, Y. et al. Appl. Phys. Lett. 84, 2685 (2004)10.1063/1.1695437Google Scholar
3. Fortunato, E. et al. Appl. Phys. Lett. 85, 2541 (2004)Google Scholar
4. Doherty, R. P. et al. Appl. Phys. A 89, 49 (2007)10.1007/s00339-007-4075-9Google Scholar
5. Henley, S. J., Ashfold, M. N. R., Nicholls, D. P., Wheatley, P., and Cherns, D.. Appl. Phys. A 79, 1169 (2004)Google Scholar
6. Lim, S. H., Shindo, D., Kang, H. B., and Nakamura, K.. J. Vac. Sci. Technol. B 19(2), 506 (2001)Google Scholar
7. Chen, Y. et al. Appl. Phys. Lett. 78, 3352 (2001)Google Scholar
8. Ohtomo, A. et al. Appl. Phys. Lett. 75, 2635 (1999)10.1063/1.125102Google Scholar
9. Gibart, P.. Rep. Prog. Phys. 67, 667 (2004)Google Scholar
10. Andeen, D., Kim, J. H., Lange, F. F., Goh, G. K. L., and Tripathy, S.. Adv. Func. Mat. 16, 799 (2005)10.1002/adfm.200500817Google Scholar
11. Vayssieres, L. and Keis, K.. Chem. Mater. 13, 4395 (2001)10.1021/cm011160sGoogle Scholar
12. Sun, Y. K. and Cherns, D.. J. App. Phys. submitted (2007)Google Scholar
13. Meshi, L. et al. J. Cryst. Growt. submitted (2007)Google Scholar
14. Nicholls, D. P., Vincent, R., Cherns, D., Sun, Y., and Ashfold, M. N. R.. Phil. Mag. Lett. 87, 417 (2007)10.1080/09500830701203164Google Scholar