Atomic-scale mapping of quantum dots formed by droplet epitaxy

Divine P. Kumah, Sergey Shusterman, Yossi Paltiel, Yizhak Yacoby, Roy Clarke*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

47 Scopus citations


Quantum dots (QDs) have applications in optoelectronic devices, quantum information processing and energy harvesting. Although the droplet epitaxy fabrication method allows for a wide range of material combinations to be used, little is known about the growth mechanisms involved. Here we apply direct X-ray methods to derive sub-ngström resolution maps of QDs crystallized from indium droplets exposed to antimony, as well as their interface with a GaAs (100) substrate. We find that the QDs form coherently and extend a few unit cells below the substrate surface. This facilitates a droplet-substrate exchange of atoms, resulting in core-shell structures that contain a surprisingly small amount of In. The work provides the first atomic-scale mapping of the interface between epitaxial QDs and a substrate, and establishes the usefulness of X-ray phasing techniques for this and similar systems.

Original languageAmerican English
Pages (from-to)835-838
Number of pages4
JournalNature Nanotechnology
Issue number12
StatePublished - Dec 2009

Bibliographical note

Funding Information:
The work was supported by the US National Science Foundation under Grant DMR-0606048. Synchrotron radiation facilities at the Advanced Photon Source were supported by DOE Contract No. DE-AC02-06CH11357. The authors are grateful to N. Husseini for useful discussions and comments.


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