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Indium clustering in a -plane InGaN quantum wells as evidenced by atom probe tomography


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Authors

Tang, F 
Oehler, F 
Fu, WY 
Griffiths, JT 

Abstract

jats:pAtom probe tomography (APT) has been used to characterize the distribution of In atoms within non-polar a-plane InGaN quantum wells (QWs) grown on a GaN pseudo-substrate produced using epitaxial lateral overgrowth. Application of the focused ion beam microscope enabled APT needles to be prepared from the low defect density regions of the grown sample. A complementary analysis was also undertaken on QWs having comparable In contents grown on polar c-plane sample pseudo-substrates. Both frequency distribution and modified nearest neighbor analyses indicate a statistically non-randomized In distribution in the a-plane QWs, but a random distribution in the c-plane QWs. This work not only provides insights into the structure of non-polar a-plane QWs but also shows that APT is capable of detecting as-grown nanoscale clustering in InGaN and thus validates the reliability of earlier APT analyses of the In distribution in c-plane InGaN QWs which show no such clustering.</jats:p>

Description

Keywords

Quantum wells, Cluster analysis, Epitaxy, Statistical analysis, Transmission electron microscopy

Journal Title

Applied Physics Letters

Conference Name

Journal ISSN

0003-6951
1077-3118

Volume Title

106

Publisher

AIP Publishing
Sponsorship
Engineering and Physical Sciences Research Council (EP/H047816/1)
Engineering and Physical Sciences Research Council (EP/J003603/1)
European Research Council (279361)
The European Research Council has provided financial support under the European Community’s Seventh Framework Programme (FP7/2007-2013)/ERC Grant Agreement No. 279361 (MACONS). This work was also funded in part by the EPSRC (Grant Nos. EP/H047816/1, EP/H0495331 and EP/J003603/1).