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

Eales, T. D. et al. (2019) Ge1-xSnx alloys: consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration. Scientific Reports, 9, 14077. (doi: 10.1038/s41598-019-50349-z) (PMID:31575881) (PMCID:PMC6773784)

Abstract

In 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.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Marko, Dr Igor and Sweeney, Professor Stephen
• Authors: Eales, T. D., Marko, I., 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.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Scientific Reports
• Publisher: Nature Research
• ISSN: 2045-2322
• ISSN (Online): 2045-2322
• Copyright Holders: Copyright: © The Author(s) 2019
• First Published: First published in Scientific Reports 9: 14077
• Publisher Policy: Reproduced under a Creative Commons licence