Band-gap and strain engineering in GeSn alloys using post-growth pulsed laser melting

O Steuer; D Schwarz; M Oehme; J Schulze; H Mączko; R Kudrawiec; I A Fischer; R Heller; R Hübner; M M Khan; Y M Georgiev; S Zhou; M Helm; S Prucnal

doi:10.1088/1361-648X/aca3ea

Band-gap and strain engineering in GeSn alloys using post-growth pulsed laser melting

J Phys Condens Matter. 2022 Dec 14;35(5). doi: 10.1088/1361-648X/aca3ea.

Authors

O Steuer¹, D Schwarz², M Oehme², J Schulze³, H Mączko⁴, R Kudrawiec⁴, I A Fischer⁵, R Heller¹, R Hübner¹, M M Khan¹, Y M Georgiev^{1

6}, S Zhou¹, M Helm¹, S Prucnal¹

Affiliations

¹ Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden, Germany.
² University of Stuttgart, Institute of Semiconductor Engineering, 70569 Stuttgart, Germany.
³ Fraunhofer Institute for Integrated Systems and Device Technology IISB, 91058 Erlangen, Germany.
⁴ Department of Semiconductor Materials Engineering, Faculty of Fundamental Problems of Technology, Wroclaw University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
⁵ Experimental Physics and Functional Materials, Brandenburgische Technische Universität Cottbus-Senftenberg, 03046 Cottbus, Germany.
⁶ Institute of Electronics, Bulgarian Academy of Sciences, 72, Tsarigradsko Chausse Blvd, 1784 Sofia, Bulgaria.

PMID: 36395508
DOI: 10.1088/1361-648X/aca3ea

Abstract

The pseudomorphic growth of Ge_1-xSn_xon Ge causes in-plane compressive strain, which degrades the superior properties of the Ge_1-xSn_xalloys. Therefore, efficient strain engineering is required. In this article, we present strain and band-gap engineering in Ge_1-xSn_xalloys grown on Ge a virtual substrate using post-growth nanosecond pulsed laser melting (PLM). Micro-Raman and x-ray diffraction (XRD) show that the initial in-plane compressive strain is removed. Moreover, for PLM energy densities higher than 0.5 J cm^-2, the Ge_0.89Sn_0.11layer becomes tensile strained. Simultaneously, as revealed by Rutherford Backscattering spectrometry, cross-sectional transmission electron microscopy investigations and XRD the crystalline quality and Sn-distribution in PLM-treated Ge_0.89Sn_0.11layers are only slightly affected. Additionally, the change of the band structure after PLM is confirmed by low-temperature photoreflectance measurements. The presented results prove that post-growth ns-range PLM is an effective way for band-gap and strain engineering in highly-mismatched alloys.

Keywords: GeSn; MBE; PLM; band gap; group IV; pulse laser melting; strain.

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