Ge1-xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration

dc.contributor.authorMarko, Igor P.
dc.contributor.authorSchulz, Stefan
dc.contributor.authorO'Halloran, Edmond
dc.contributor.authorGhetmiri, Seyed
dc.contributor.authorDu, Wei
dc.contributor.authorZhou, Yiyin
dc.contributor.authorYu, Shui-Qing
dc.contributor.authorMargetis, Joe
dc.contributor.authorTolle, John
dc.contributor.authorO'Reilly, Eoin P.
dc.contributor.authorSweeney, Stephen J.
dc.contributor.funderEngineering and Physical Sciences Research Councilen
dc.contributor.funderScience Foundation Irelanden
dc.contributor.funderAir Force Office of Scientific Researchen
dc.description.abstractIn this work we study the nature of the band gap in GeSn alloys for use in silicon-based lasers. Special attention is paid to Sn-induced band mixing effects. We demonstrate from both experiment and ab-initio theory that the (direct) Γ-character of the GeSn band gap changes continuously with alloy composition and has significant Γ-character even at low (6%) Sn concentrations. The evolution of the Γ-character is due to Sn-induced conduction band mixing effects, in contrast to the sharp indirect-to-direct band gap transition obtained in conventional alloys such as Al1−xGaxAs. Understanding the band mixing effects is critical not only from a fundamental and basic properties viewpoint but also for designing photonic devices with enhanced capabilities utilizing GeSn and related material systems.en
dc.description.sponsorshipEPSRC (Projects EP/H005587/01, and EP/N021037/1); Air Force Office of Scientific Research (AFOSR) (FA9550-14-1-0205)en
dc.description.statusPeer revieweden
dc.description.versionPublished Versionen
dc.identifier.citationEales, T. D., Marko, I. P., Schulz, S., O’Halloran, E., Ghetmiri, S., Du, W., Zhou, Y., Yu, S.-Q., Margetis, J., Tolle, J., O’Reilly, E. P. and Sweeney, S. J. (2019) 'Ge1−xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration', Scientific Reports, 9(1), 14077. (10pp.) DOI: 10.1038/s41598-019-50349-zen
dc.identifier.journaltitleScientific reportsen
dc.publisherSpringer Natureen
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Starting Investigator Research Grant (SIRG)/13/SIRG/2210/IE/Shaping the electronic and optical properties of non- and semi-polar nitride-based semiconductor nanostructures/en
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Investigator Programme/14/IA/2513/IE/Silicon Compatible, Direct Band-Gap Nanowire Materials For Beyond-CMOS Devices/en
dc.relation.projectinfo:eu-repo/grantAgreement/SFI/SFI Investigator Programme/15/IA/3082/IE/Multiscale Simulation and Analysis of emerging Group IV and III-V Semiconductor Materials and Devices/en
dc.relation.projectinfo:eu-repo/grantAgreement/NSF/Directorate for Mathematical & Physical Sciences::Division of Materials Research/1149605/US/CAREER: High Performance III-V-Bismide Mid-Infrared Semiconductor Lasers/en
dc.rights© The Author(s) 2019. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as 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. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit
dc.subjectElectronic structureen
dc.subjectSilicon photonicsen
dc.subjectBand mixing effectsen
dc.titleGe1-xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentrationen
dc.typeArticle (peer-reviewed)en
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