Journal Article

FZJ-2024-01644

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Thermal expansion and temperature dependence of Raman modes in epitaxial layers of Ge and Ge 1 − x Sn x

Corley-Wiciak, A. A.FZJ* ; Ryzhak, D. ; Zoellner, M. H. ; Manganelli, C. L. ; Concepción, O.FZJ* ; Skibitzki, O. ; Grützmacher, D.FZJ* ; Buca, D.FZJ* ; Capellini, G. ; Spirito, D. (Corresponding author)

2024
APS College Park, MD

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Please use a persistent id in citations: doi:10.1103/PhysRevMaterials.8.023801  doi:10.34734/FZJ-2024-01644

Abstract: 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.

Keyword(s): Basic research (1st) ; Materials Science (2nd)

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Contributing Institute(s):

1. Halbleiter-Nanoelektronik (PGI-9)

Research Program(s):

1. 5234 - Emerging NC Architectures (POF4-523) (POF4-523)

Appears in the scientific report 2024

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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