• Georgiev, Yordan M.
• Oehme, Michael
• Steuer, Oliver
• Schwarz, Daniel
• Mączko, H.
• Kudrawiec, Robert
• Heller, R.
• Hübner, R.
• Helm, M.
• Fischer, I. A.
• Prucnal, Slawomir
• Zhou, Shengqiang
• Khan, M. M.
• Schulze, J.

Abstract

<jats:title>Abstract</jats:title><jats:p>The pseudomorphic growth of Ge<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>Sn<jats:italic><jats:sub>x</jats:sub></jats:italic> on Ge causes in-plane compressive strain, which degrades the superior properties of the Ge<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>Sn<jats:italic><jats:sub>x</jats:sub></jats:italic> alloys. Therefore, efficient strain engineering is required. In this article, we present strain and band-gap engineering in Ge<jats:sub>1−<jats:italic>x</jats:italic></jats:sub>Sn<jats:italic><jats:sub>x</jats:sub></jats:italic> alloys 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<jats:sup>−2</jats:sup>, the Ge<jats:sub>0.89</jats:sub>Sn<jats:sub>0.11</jats:sub> layer 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<jats:sub>0.89</jats:sub>Sn<jats:sub>0.11</jats:sub> layers 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.</jats:p>

Topics

• impedance spectroscopy
• x-ray diffraction
• transmission electron microscopy
• spectrometry
• band structure
• Rutherford backscattering spectrometry