Browsing by Author "Lai, SK"

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Observations of Al segregation around dislocations in AlGaN
(2001-08-13)
Chang, L
;
Lai, SK
;
Chen, FR
;
Kai, JJ
;
材料科學與工程學系
Transmission electron microscopy has been used to observe Al segregation around the threading dislocations in Al0.1Ga0.9N and Al0.3Ga0.7N grown by metalorganic chemical vapor deposition on 6H-SiC. Dislocation lines were found to have up to 70% more Al concentration than those regions free of dislocations in the matrix. The Al-depleted regions around the dislocations are shown to be within a few nanometers from the dislocation lines. The results also show that more Al segregate to edge dislocations than to screw ones. (C) 2001 American Institute of Physics.
Observations of segregation of Al in AlGaN alloys
(2001-11-23)
Chang, L
;
Lai, SK
;
Chen, FR
;
Kai, JJ
;
材料科學與工程學系
Transmission electron microscopy has been used to characterize Al segregation in Al0.1Ga0.9N and Al0.3Ga0.7N alloys grown by metal organic chemical vapor deposition on 6H-SiC. It has been found that an interlayer of AlGaN alloy with much higher Al content was formed at first, followed by normal growth of nominal composition of AlGaN alloy. In Al0.1Ga0.9N and Al0.3Ga0.7N films. dislocation lines were also found to have more Al segregated than those regions free of dislocations in the matrix. Furthermore, it shows that more Al atoms segregate to an edge dislocation than to a screw one.