Raman scattering in Ge1-ySny alloys

V. R. D'Costa; J. Tolle; R. Roucka; C. D. Poweleit; John Kouvetakis; Jose Menendez

doi:10.1016/j.ssc.2007.08.020

Raman scattering in Ge_1-ySn_y alloys

V. R. D'Costa, J. Tolle, R. Roucka, C. D. Poweleit, John Kouvetakis, Jose Menendez

Research output: Contribution to journal › Article › peer-review

95 Scopus citations

Abstract

The Raman spectrum of nearly relaxed Ge_1-ySn_y alloys grown on Si substrates was investigated for Sn concentrations y < 0.2. The frequency dependence of the Ge-Ge Raman mode was re-evaluated by carrying out careful corrections for residual strain shifts. The Ge-Sn mode was observed for the first time in this type of samples. Its frequency appears to decrease monotonically as a function of the Sn concentration. This is very different from the behavior of the Si-Ge mode in Si_1-yGe_y alloys, but a detailed analysis suggest that there is a scaling relationship between these modes that is the analog of the scaling relationship found earlier for the Ge-Ge mode. Raman activity is also found in the spectral range where Sn-Sn modes are expected, but the polarization properties of these features suggest an overlap with disorder-activated Ge-acoustic phonons. Additional features observed in "forbidden" scattering configurations are also assigned to disorder-activated Raman scattering.

Original language	English (US)
Pages (from-to)	240-244
Number of pages	5
Journal	Solid State Communications
Volume	144
Issue number	5-6
DOIs	https://doi.org/10.1016/j.ssc.2007.08.020
State	Published - Nov 1 2007

Keywords

A. Semiconductors
D. Raman scattering

ASJC Scopus subject areas

Chemistry(all)
Condensed Matter Physics
Materials Chemistry

Access to Document

10.1016/j.ssc.2007.08.020

Cite this

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title = "Raman scattering in Ge1-ySny alloys",

abstract = "The Raman spectrum of nearly relaxed Ge1-ySny alloys grown on Si substrates was investigated for Sn concentrations y < 0.2. The frequency dependence of the Ge-Ge Raman mode was re-evaluated by carrying out careful corrections for residual strain shifts. The Ge-Sn mode was observed for the first time in this type of samples. Its frequency appears to decrease monotonically as a function of the Sn concentration. This is very different from the behavior of the Si-Ge mode in Si1-yGey alloys, but a detailed analysis suggest that there is a scaling relationship between these modes that is the analog of the scaling relationship found earlier for the Ge-Ge mode. Raman activity is also found in the spectral range where Sn-Sn modes are expected, but the polarization properties of these features suggest an overlap with disorder-activated Ge-acoustic phonons. Additional features observed in {"}forbidden{"} scattering configurations are also assigned to disorder-activated Raman scattering.",

keywords = "A. Semiconductors, D. Raman scattering",

author = "D'Costa, {V. R.} and J. Tolle and R. Roucka and Poweleit, {C. D.} and John Kouvetakis and Jose Menendez",

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T1 - Raman scattering in Ge1-ySny alloys

AU - D'Costa, V. R.

AU - Tolle, J.

AU - Roucka, R.

AU - Poweleit, C. D.

AU - Kouvetakis, John

AU - Menendez, Jose

PY - 2007/11/1

Y1 - 2007/11/1

N2 - The Raman spectrum of nearly relaxed Ge1-ySny alloys grown on Si substrates was investigated for Sn concentrations y < 0.2. The frequency dependence of the Ge-Ge Raman mode was re-evaluated by carrying out careful corrections for residual strain shifts. The Ge-Sn mode was observed for the first time in this type of samples. Its frequency appears to decrease monotonically as a function of the Sn concentration. This is very different from the behavior of the Si-Ge mode in Si1-yGey alloys, but a detailed analysis suggest that there is a scaling relationship between these modes that is the analog of the scaling relationship found earlier for the Ge-Ge mode. Raman activity is also found in the spectral range where Sn-Sn modes are expected, but the polarization properties of these features suggest an overlap with disorder-activated Ge-acoustic phonons. Additional features observed in "forbidden" scattering configurations are also assigned to disorder-activated Raman scattering.

AB - The Raman spectrum of nearly relaxed Ge1-ySny alloys grown on Si substrates was investigated for Sn concentrations y < 0.2. The frequency dependence of the Ge-Ge Raman mode was re-evaluated by carrying out careful corrections for residual strain shifts. The Ge-Sn mode was observed for the first time in this type of samples. Its frequency appears to decrease monotonically as a function of the Sn concentration. This is very different from the behavior of the Si-Ge mode in Si1-yGey alloys, but a detailed analysis suggest that there is a scaling relationship between these modes that is the analog of the scaling relationship found earlier for the Ge-Ge mode. Raman activity is also found in the spectral range where Sn-Sn modes are expected, but the polarization properties of these features suggest an overlap with disorder-activated Ge-acoustic phonons. Additional features observed in "forbidden" scattering configurations are also assigned to disorder-activated Raman scattering.

KW - A. Semiconductors

KW - D. Raman scattering

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