Oxygen segregation to nanopipes in gallium nitride

ME Hawkridge, D Cherns

Research output: Contribution to journalArticle (Academic Journal)peer-review


This paper examines the core structure and composition of threading dislocations in GaN grown by hydride vapour phase epitaxy. Transmission electron microscopy showed that screw dislocations have widely varying core structures from open cores ("nanopipes") to closed cores, with irregular variations between the two observed along the length of many dislocations. New evidence was found demonstrating that the equilibrium structure of screw dislocations is a closed core configuration. Electron energy loss spectroscopy combined with high resolution imaging showed that 1.7 +/- 0.3 monolayers of nitrogen were substituted by oxygen at the surfaces of nanopipes. In contrast, closed core dislocations showed little evidence of oxygen segregation. It is argued that these results support a model where nanopipe formation is controlled by the segregation of oxygen to pits predominately associated with, albeit not exclusively, dislocations. The implication of the results in understanding the electronic behavior of dislocations in GaN is also discussed.
Translated title of the contributionOxygen segregation to nanopipes in gallium nitride
Original languageEnglish
Pages (from-to)543 - 548
Number of pages6
JournalMaterial Research Society Symposium Proceedings
Issue numberSymposium FF – GaN, AlN, InN and Related Materials
Publication statusPublished - 2006

Bibliographical note

Editors: Kuball M, Myers TH, Redwing JM, Mukai T
Publisher: Materials Research Society
Name and Venue of Conference: Materials Research Society Fall Meeting, Boston USA, 30 Nov - 2 Dec 2005
Name and Venue of Event: Symposium on GaN, AIN, InN Related Materials
Conference Organiser: Materials Research Society


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