Hostname: page-component-77c89778f8-swr86 Total loading time: 0 Render date: 2024-07-19T06:38:36.328Z Has data issue: false hasContentIssue false

Transmission Electron Microscopy Study of Room Temperature Lasing Epitaxial ZnO Films on Sapphire

Published online by Cambridge University Press:  10 February 2011

N. Wang
Affiliation:
Department of Physics, Hong Kong University of Science and Technology, Hong Kong
K. K. Fung
Affiliation:
Department of Physics, Hong Kong University of Science and Technology, Hong Kong
P. Yu
Affiliation:
Department of Physics, Hong Kong University of Science and Technology, Hong Kong
Z. K. Tang
Affiliation:
Department of Physics, Hong Kong University of Science and Technology, Hong Kong
G. K. L. Wong
Affiliation:
Department of Physics, Hong Kong University of Science and Technology, Hong Kong
M. Kawasaki
Affiliation:
Research Laboratory of Engineering Materials, Tokyo Institute of Technology, Japan
A. Ohtomo
Affiliation:
Research Laboratory of Engineering Materials, Tokyo Institute of Technology, Japan
H. Koinuma
Affiliation:
Research Laboratory of Engineering Materials, Tokyo Institute of Technology, Japan
Y. Segawa
Affiliation:
Photodynamics Research Center, RIKEN, Sendai 980, Japan
Get access

Abstract

We have studied the microstructures of lasing and non-lasing ZnO films on sapphire in plan-view and cross-section by transmission electron microscopy (TEM). While ZnO films in general are made up of cloumnar close-packed c-axis misoriented nanocrystals, the misorientation in nonlasing film, typically 5°, is considerably larger than lasing film, typically less than 1°. A rather high density of pinholes or nanotubes is associated with the highly misoriented films. The misorientation between adjacent grains is taken up by grain boundary dislocations. Room temperature lasing films contain a high density of threading boundary edge dislocations, in excess of 1010 cm−2. But faceting in the columnar nanocrystals is not well developed so that the grain boundaries are not clearly visible. Tilting of (0001) lattice planes between grains originating from substrate surface step and growth fault step, however, has been observed in high resolution electron microscopy (HREM) images.

Type
Research Article
Copyright
Copyright © Materials Research Society 1998

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.)

Footnotes

+

Department of Physics and Materials Science, City University of Hong Kong.

References

1. Haase, M.A., Qiu, J., DePuydt, J.M. and Cheng, H., Appl. Phys. Lett. 59, 1272 (1991).Google Scholar
2. Nakamura, S., Mukai, T. and Senoh, M., Appl. Phys. Lett. 64, 1687 (1994).Google Scholar
3. Srikant, V., Sergo, V. and Clarke, D.R., J. Am. Ceram. Soc., 78, 1931 (1995).10.1111/j.1151-2916.1995.tb08912.xGoogle Scholar
4. Yu, P., Tang, Z.K., Wong, G.K.L., Kawasaki, M. and Segawa, Y., Proc. 23rd Int. Conf Phys. Semicond., edited by Scheffler, M. and Zimmermann, R. (World Scientific, Singapore, 1996), pp. 1453.Google Scholar
5. Yu, P., Tang, Z.K., Wong, G.K.L., Kawasaki, M., Ohtomo, A., Koinuma, H. and Segawa, Y., Solid State Comm. 103, 459 (1997).Google Scholar
6. Bagnall, D.M., Chen, Y.F., Zhu, Z., Yao, T., Koyama, S., Shen, M.Y. and Goto, T., Appl. Phys. Lett. 70, 2230 (1997).10.1063/1.118824Google Scholar
7. Segawa, Y., Ohtomo, A., Kawasaki, M., Koinuma, H., Tang, Z.K., Yu, P. and Wong, G.K.L., phys. stat. sol. (b) 202, 669 (1997).10.1002/1521-3951(199708)202:2<669::AID-PSSB669>3.0.CO;2-T3.0.CO;2-T>Google Scholar
8. Qian, W., Rohrer, G.S., Skowronski, M., Doverspike, K., Rowland, L.B. and Gaskill, D.K., Appl. Phys. Lett. 67, 2284 (1995).Google Scholar
9. Qian, W., Skowronski, M., De Graef, M., Doverspike, K., Rowland, L.B. and Gaskill, D.K., Appl. Phys. Lett. 66, 1252 (1995).Google Scholar
10. Heying, B., Wu, X.H., Keller, S., Ji, Y., Kapolnek, D., Keller, B.P., Denbaars, S.P. and Speck, J.S., Appl. Phys. Lett., 68, 643 (1996)10.1063/1.116495Google Scholar
11. Ning, X.J., Chien, F.R., Pirouz, P., Yang, J.W. and Khan, M. Asif, J. Mater. Res. 11, 580 (1996).10.1557/JMR.1996.0071Google Scholar