TY - JOUR
T1 - Optical critical points of thin-film Ge1-y Sny alloys
T2 - A comparative Ge1-y Sny Ge1-x six study
AU - D'Costa, Vijay R.
AU - Cook, Candi S.
AU - Birdwell, A. G.
AU - Littler, Chris L.
AU - Canonico, Michael
AU - Zollner, Stefan
AU - Kouvetakis, John
AU - Menendez, Jose
PY - 2006/4/6
Y1 - 2006/4/6
N2 - The E0, E0 + Δ0, E1, E1 + Δ1, E0′, and E2 optical transitions have been measured in Ge1-y Sny alloys (y<0.2) using spectroscopic ellipsometry and photoreflectance. The results indicate a strong nonlinearity (bowing) in the compositional dependence of these quantities. Such behavior is not predicted by electronic structure calculations within the virtual crystal approximation. The bowing parameters for Ge1-y Sny alloys show an intriguing correlation with the corresponding bowing parameters in the Ge1-x Six system, suggesting a scaling behavior for the electronic properties that is the analog of the scaling behavior found earlier for the vibrational properties. A direct consequence of this scaling behavior is a significant reduction (relative to prior theoretical estimates within the virtual crystal approximation) of the concentration yc for a crossover from an indirect- to a direct-gap system.
AB - The E0, E0 + Δ0, E1, E1 + Δ1, E0′, and E2 optical transitions have been measured in Ge1-y Sny alloys (y<0.2) using spectroscopic ellipsometry and photoreflectance. The results indicate a strong nonlinearity (bowing) in the compositional dependence of these quantities. Such behavior is not predicted by electronic structure calculations within the virtual crystal approximation. The bowing parameters for Ge1-y Sny alloys show an intriguing correlation with the corresponding bowing parameters in the Ge1-x Six system, suggesting a scaling behavior for the electronic properties that is the analog of the scaling behavior found earlier for the vibrational properties. A direct consequence of this scaling behavior is a significant reduction (relative to prior theoretical estimates within the virtual crystal approximation) of the concentration yc for a crossover from an indirect- to a direct-gap system.
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U2 - 10.1103/PhysRevB.73.125207
DO - 10.1103/PhysRevB.73.125207
M3 - Article
AN - SCOPUS:33645456449
VL - 73
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 0163-1829
IS - 12
M1 - 125207
ER -