GaSb/GaAs quantum dot formation and demolition studied with cross-sectional scanning tunneling microscopy

E.P. Smakman, J.K. Garleff, R.J. Young, M. Hayne, P. Rambabu, P.M. Koenraad

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

We present a cross-sectional scanning tunneling microscopy study of GaSb/GaAs quantum dots grown by molecular beam epitaxy. Various nanostructures are observed as a function of the growth parameters. During growth, relaxation of the high local strain fields of the nanostructures plays an important role in their formation. Pyramidal dots with a high Sb content are often accompanied by threading dislocations above them. GaSb ring formation is favored by the use of a thin GaAs first cap layer and a high growth temperature of the second cap layer. At these capping conditions, strain-driven Sb diffusion combined with As/Sb exchange and Sb segregation remove the center of a nanostructure, creating a ring. Clusters of GaSb without a well defined morphology also appear regularly, often with a highly inhomogeneous structure which is sometimes divided up in fragments.
Original languageEnglish
Article number142116
Pages (from-to)142116-1/3
Number of pages3
JournalApplied Physics Letters
Volume100
Issue number14
DOIs
Publication statusPublished - 2012

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