Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1 - ySny alloys

J. D. Gallagher, C. L. Senaratne, John Kouvetakis, Jose Menendez

Research output: Contribution to journalArticle

58 Citations (Scopus)

Abstract

Photoluminescence spectroscopy has been used to determine the direct gap E0 of Ge1- ySny alloys over a broad compositional range from pure Ge to Sn concentrations exceeding 10%. A fit of the compositional dependence of E0 using a standard quadratic expression is not fully satisfactory, revealing that the bowing parameter (quadratic coefficient) b0 is compositionally dependent. Excellent agreement with the data is obtained with b0(y) = (2.66 ± 0.09) eV - (5.4 ± 1.1)y eV. A theoretical model of the bowing is presented, which explains the strong compositional dependence of the bowing parameter and suggest a similar behavior for the indirect gap. Combining the model predictions with experimental data for samples with y ≤ 0.06, it is proposed that the bowing parameter for the indirect gap is bind(y) = (1.11 ± 0.07) eV - (0.78 ± 0.05)y eV. The compositional dependence of the bowing parameters shifts the crossover concentration from indirect to direct gap behavior to yc = 0.087, significantly higher than the value predicted earlier based on strictly quadratic fits.

Original languageEnglish (US)
Article number142102
JournalApplied Physics Letters
Volume105
Issue number14
DOIs
StatePublished - Oct 6 2014

Fingerprint

crossovers
photoluminescence
shift
coefficients
predictions
spectroscopy

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1 - ySny alloys. / Gallagher, J. D.; Senaratne, C. L.; Kouvetakis, John; Menendez, Jose.

In: Applied Physics Letters, Vol. 105, No. 14, 142102, 06.10.2014.

Research output: Contribution to journalArticle

@article{a436309e72d74322bf84129891fd9a35,
title = "Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1 - ySny alloys",
abstract = "Photoluminescence spectroscopy has been used to determine the direct gap E0 of Ge1- ySny alloys over a broad compositional range from pure Ge to Sn concentrations exceeding 10{\%}. A fit of the compositional dependence of E0 using a standard quadratic expression is not fully satisfactory, revealing that the bowing parameter (quadratic coefficient) b0 is compositionally dependent. Excellent agreement with the data is obtained with b0(y) = (2.66 ± 0.09) eV - (5.4 ± 1.1)y eV. A theoretical model of the bowing is presented, which explains the strong compositional dependence of the bowing parameter and suggest a similar behavior for the indirect gap. Combining the model predictions with experimental data for samples with y ≤ 0.06, it is proposed that the bowing parameter for the indirect gap is bind(y) = (1.11 ± 0.07) eV - (0.78 ± 0.05)y eV. The compositional dependence of the bowing parameters shifts the crossover concentration from indirect to direct gap behavior to yc = 0.087, significantly higher than the value predicted earlier based on strictly quadratic fits.",
author = "Gallagher, {J. D.} and Senaratne, {C. L.} and John Kouvetakis and Jose Menendez",
year = "2014",
month = "10",
day = "6",
doi = "10.1063/1.4897272",
language = "English (US)",
volume = "105",
journal = "Applied Physics Letters",
issn = "0003-6951",
publisher = "American Institute of Physics Publising LLC",
number = "14",

}

TY - JOUR

T1 - Compositional dependence of the bowing parameter for the direct and indirect band gaps in Ge1 - ySny alloys

AU - Gallagher, J. D.

AU - Senaratne, C. L.

AU - Kouvetakis, John

AU - Menendez, Jose

PY - 2014/10/6

Y1 - 2014/10/6

N2 - Photoluminescence spectroscopy has been used to determine the direct gap E0 of Ge1- ySny alloys over a broad compositional range from pure Ge to Sn concentrations exceeding 10%. A fit of the compositional dependence of E0 using a standard quadratic expression is not fully satisfactory, revealing that the bowing parameter (quadratic coefficient) b0 is compositionally dependent. Excellent agreement with the data is obtained with b0(y) = (2.66 ± 0.09) eV - (5.4 ± 1.1)y eV. A theoretical model of the bowing is presented, which explains the strong compositional dependence of the bowing parameter and suggest a similar behavior for the indirect gap. Combining the model predictions with experimental data for samples with y ≤ 0.06, it is proposed that the bowing parameter for the indirect gap is bind(y) = (1.11 ± 0.07) eV - (0.78 ± 0.05)y eV. The compositional dependence of the bowing parameters shifts the crossover concentration from indirect to direct gap behavior to yc = 0.087, significantly higher than the value predicted earlier based on strictly quadratic fits.

AB - Photoluminescence spectroscopy has been used to determine the direct gap E0 of Ge1- ySny alloys over a broad compositional range from pure Ge to Sn concentrations exceeding 10%. A fit of the compositional dependence of E0 using a standard quadratic expression is not fully satisfactory, revealing that the bowing parameter (quadratic coefficient) b0 is compositionally dependent. Excellent agreement with the data is obtained with b0(y) = (2.66 ± 0.09) eV - (5.4 ± 1.1)y eV. A theoretical model of the bowing is presented, which explains the strong compositional dependence of the bowing parameter and suggest a similar behavior for the indirect gap. Combining the model predictions with experimental data for samples with y ≤ 0.06, it is proposed that the bowing parameter for the indirect gap is bind(y) = (1.11 ± 0.07) eV - (0.78 ± 0.05)y eV. The compositional dependence of the bowing parameters shifts the crossover concentration from indirect to direct gap behavior to yc = 0.087, significantly higher than the value predicted earlier based on strictly quadratic fits.

UR - http://www.scopus.com/inward/record.url?scp=84907937926&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84907937926&partnerID=8YFLogxK

U2 - 10.1063/1.4897272

DO - 10.1063/1.4897272

M3 - Article

AN - SCOPUS:84907937926

VL - 105

JO - Applied Physics Letters

JF - Applied Physics Letters

SN - 0003-6951

IS - 14

M1 - 142102

ER -