Ge1−xSnx alloys: Consequences of band mixing effects for the evolution of the band gap Γ-character with Sn concentration
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.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2019
- Source ID
- 10.1038/s41598-019-50349-z
Entities
People
- Edmond O’halloran
- Eoin P. O’reilly
- Igor P. Marko
- Joe Margetis
- John Tolle
- Seyed Amir Ghetmiri
- Shui-Qing Yu
- Stefan Schulz
- Stephen J Sweeney
- Timothy D. Eales
- Wei Du
- Yiyin Zhou
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- Science Foundation Ireland