This title appears in the Scientific Report :
2024
Please use the identifier:
http://dx.doi.org/10.34734/FZJ-2024-01644 in citations.
Please use the identifier: http://dx.doi.org/10.1103/PhysRevMaterials.8.023801 in citations.
Thermal expansion and temperature dependence of Raman modes in epitaxial layers of Ge and Ge 1 − x Sn x
Thermal expansion and temperature dependence of Raman modes in epitaxial layers of Ge and Ge 1 − x Sn x
Temperature dependence of vibrational modes in semiconductors depends on lattice thermal expansion andanharmonic phonon-phonon scattering. Evaluating the two contributions from experimental data is not straightforward,especially for epitaxial layers that present mechanical deformation and anisotropi...
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Personal Name(s): | Corley-Wiciak, Agnieszka Anna |
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Ryzhak, Diana / Zoellner, Marvin Hartwig / Manganelli, Costanza Lucia / Concepción, Omar / Skibitzki, Oliver / Grützmacher, Detlev / Buca, Dan / Capellini, Giovanni / Spirito, Davide (Corresponding author) | |
Contributing Institute: |
Halbleiter-Nanoelektronik; PGI-9 |
Published in: | Physical review materials, 8 (2024) 2, S. 023801 |
Imprint: |
College Park, MD
APS
2024
|
DOI: |
10.34734/FZJ-2024-01644 |
DOI: |
10.1103/PhysRevMaterials.8.023801 |
Document Type: |
Journal Article |
Research Program: |
Emerging NC Architectures |
Subject (ZB): | |
Link: |
OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1103/PhysRevMaterials.8.023801 in citations.
Temperature dependence of vibrational modes in semiconductors depends on lattice thermal expansion andanharmonic phonon-phonon scattering. Evaluating the two contributions from experimental data is not straightforward,especially for epitaxial layers that present mechanical deformation and anisotropic lattice expansion.In this paper, a temperature-dependent Raman study in epitaxial Ge and Ge1−xSnx layers is presented. A modelis introduced for the Raman mode energy shift as a function of temperature, comprising thermal expansion ofthe strained lattice and anharmonic corrections. With support of x-ray diffraction, the model is calibrated onexperimental data of epitaxial Ge grown on Si and Ge1−xSnx grown on Ge/Si, finding that the main differencebetween bulk and epitaxial layers is related to the anisotropic lattice expansion. The phonon anharmonicity andother parameters do not depend on dislocation defect density (in the range 7×106 – 4×108 cm−2) nor on alloycomposition in the range 5–14 at.%. The strain-shift coefficient for the main model of Ge and for the Ge-Gevibrational mode of Ge1−xSnx is weakly dependent on temperature and is around –500 cm–1. In Ge1−xSnx, thecomposition-shift coefficient amounts to –100 cm-1, independent of temperature and strain. |