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Dislocations around precipitates in AlGaN epilayers

Published online by Cambridge University Press:  31 January 2011

Junyong Kang ,
Shin Tsunekawa  and
Atsuo Kasuya
Junyong Kang*
Affiliation:
Department of Physics, Xiamen University, Xiamen 361005, People's Republic of China
Shin Tsunekawa
Affiliation:
Institute for Materials Research, Tohoku University, Sendai 80–8577, Japan
Atsuo Kasuya
Affiliation:
Center for Interdisciplinary Research, Tohoku University, Aoba-ku, Sendai 980–8578, Japan
*
a)Address all correspondence to this author.jykang@xmu.ed.cn
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Abstract

Dislocations around precipitates in undoped AlGaN were investigated by transmission electron microscopy. The dislocation images were taken under different diffraction conditions. The dislocations are classified into two types, a pure edge dislocation loop and a close-;coiled helical dislocation. Both types of dislocations were found to depend on the shape and size of the precipitate sources. It is suggested that the pure edge dislocation loop results from homogeneous shear stress and the close-;coiled helical dislocation is caused by spherically symmetrical stress concentration at round ends of the precipitates and chemical force due to defect concentration change.

Type
Articles
Information
Journal of Materials Research , Volume 17 , Issue 8 , August 2002 , pp. 2007 - 2011
Copyright
Copyright © Materials Research Society 2002

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