Droplet etching of deep nanoholes for filling with self-aligned complex quantum structures

dc.contributor.authorKüster, Achim
dc.contributor.authorHeyn, Christian
dc.contributor.authorUngeheuer, Arne
dc.contributor.authorJuska, Gediminas
dc.contributor.authorTommaso Moroni, Stefano
dc.contributor.authorPelucchi, Emanuele
dc.contributor.authorHansen, Wolfgang
dc.contributor.funderScience Foundation Irelanden
dc.date.accessioned2016-10-05T11:41:49Z
dc.date.available2016-10-05T11:41:49Z
dc.date.issued2016-06-03
dc.description.abstractStrain-free epitaxial quantum dots (QDs) are fabricated by a combination of Al local droplet etching (LDE) of nanoholes in AlGaAs surfaces and subsequent hole filling with GaAs. The whole process is performed in a conventional molecular beam epitaxy (MBE) chamber. Autocorrelation measurements establish single-photon emission from LDE QDs with a very small correlation function g (2)(0)≃ 0.01 of the exciton emission. Here, we focus on the influence of the initial hole depth on the QD optical properties with the goal to create deep holes suited for filling with more complex nanostructures like quantum dot molecules (QDM). The depth of droplet etched nanoholes is controlled by the droplet material coverage and the process temperature, where a higher coverage or temperature yields deeper holes. The requirements of high quantum dot uniformity and narrow luminescence linewidth, which are often found in applications, set limits to the process temperature. At high temperatures, the hole depths become inhomogeneous and the linewidth rapidly increases beyond 640 °C. With the present process technique, we identify an upper limit of 40-nm hole depth if the linewidth has to remain below 100 μeV. Furthermore, we study the exciton fine-structure splitting which is increased from 4.6 μeV in 15-nm-deep to 7.9 μeV in 35-nm-deep holes. As an example for the functionalization of deep nanoholes, self-aligned vertically stacked GaAs QD pairs are fabricated by filling of holes with 35 nm depth. Exciton peaks from stacked dots show linewidths below 100 μeV which is close to that from single QDs.en
dc.description.sponsorshipDeutsche Forschungsgemeinschaft, Germany (HA 2042/6-1 and GrK 1286 ); Science Foundation Ireland (SFI grants 12/RC/2276 and 10/IN.1/I3000)en
dc.description.statusPeer revieweden
dc.description.versionPublished Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationKüster, A., Heyn, C., Ungeheuer, A., Juska, G., Tommaso Moroni, S., Pelucchi, E. & Hansen, W. (2016) ‘Droplet etching of deep nanoholes for filling with self-aligned complex quantum structures’, Nanoscale Research Letters, 11, 282, 1-7. doi: 10.1186/s11671-016-1495-5en
dc.identifier.doi10.1186/s11671-016-1495-5
dc.identifier.endpage282-7en
dc.identifier.issn1931-7573
dc.identifier.journaltitleNanoscale Research Lettersen
dc.identifier.startpage282-1en
dc.identifier.urihttps://hdl.handle.net/10468/3156
dc.language.isoenen
dc.publisherSpringer Openen
dc.rights© 2016 Küster et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.en
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/en
dc.subjectSemiconductoren
dc.subjectNanostructuringen
dc.subjectSelf-assemblyen
dc.subjectDroplet etchingen
dc.subjectQuantum doten
dc.titleDroplet etching of deep nanoholes for filling with self-aligned complex quantum structuresen
dc.typeArticle (peer-reviewed)en
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