Strain engineering in Ge/GeSn core/shell nanowires

Abstract

Strain engineering in Sn-rich group IV semiconductors is a key enabling factor to exploit the direct band gap at mid-infrared wavelengths. Here, we investigate the effect of strain on the growth of GeSn alloys in a Ge/GeSn core/shell nanowire geometry. Incorporation of Sn content in the 10-20 at.% range is achieved with Ge core diameters ranging from 50nm to 100nm. While the smaller cores lead to the formation of a regular and homogeneous GeSn shell, larger cores lead to the formation of multi-faceted sidewalls and broadened segregation domains, inducing the nucleation of defects. This behavior is rationalized in terms of the different residual strain, as obtained by realistic finite element method simulations. The extended analysis of the strain relaxation as a function of core and shell sizes, in comparison with the conventional planar geometry, provides a deeper understanding of the role of strain in the epitaxy of metastable GeSn semiconductors.

References in corpus (4)

• Optically pumped GeSn micro-disks with 16 % Sn lasing at 3.1 um up to 180K
• Direct Bandgap Light Emission from Strained Ge Nanowires Coupled with High-Q Optical Cavities
• Morphology of epitaxial core-shell nanowires
• Enhanced IR Light Absorption in Group IV-SiGeSn Core-Shell Nanowires

Cited by in corpus (5)

• Efficient strain-induced light emission in lonsdaleite germanium
• Kinetic Control of Morphology and Composition in Ge/GeSn Core/Shell Nanowires
• Extended-SWIR Photodetection in All-Group IV Core/Shell Nanowires
• Transfer-printed multiple Ge${}_{0.89}$Sn${}_{0.11}$ membrane mid-infrared photodetectors
• Ge-Ge${}_{0.92}$Sn${}_{0.08}$ core-shell single nanowire infrared photodetector with superior characteristics for on-chip optical communication