Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices

G. Leibiger, V. Gottschalch, A. Kasik, B. Rheinländer, J. Ŝik, Mathias Schubert

Research output: Contribution to conferencePaper

1 Citation (Scopus)

Abstract

Spectroscopic ellipsometry (SE) is employed to study the optical properties of tensile (compressive) strained GaAs1-yNy(InAs)/GaAs [0% ≤ y ≤ 3.3%] superlattices and GaAs1-yNy [0% ≤ y ≤ 3.7%] single layers for photon energies from 0.75 eV to 4.5 eV and for wavenumbers from 100 cm-1 to 600 cm-1. We provide parametric model functions for the dielectric function spectra of GaAsN in both photon energy ranges. The model functions for photon energies from 0.75 eV to 4.5 eV excellently match dielectric function data obtained from a numerical wavelength-by-wavelength inversion of the experimental data. Critical-point analysis of the ellipsometric data is performed in the spectral regions of the fundamental band gap and the critical points E1 and E11. The band-gap energy is red shifted whereas the E1 and E11 transition energies are blue shifted with increasing y. For y ≤ 1.65% the observed blue shift of the E1 energy is well explained by the sum of the effects of biaxial (001) strain and alloying. The GaAsN layers show two-mode behaviour in the infrared spectral range (100 cm-1 to 600 cm-1). We detect the transverse GaAs- and GaN- sublattice modes at wavenumbers of about 267 cm-1 and 470 cm-1, respectively. The polar strength of the GaN TO mode increases linearly with y, but with different slopes for the GaAsN/GaAs and GaAsN/InAs/GaAs superlattices, respectively. This is due to the different strain states. This effect can be used to monitor strain or nitrogen composition in GaAsN layers. We further detect free carriers in the GaAsN sublayers of the GaAsN/GaAs superlattices. The absence of free carriers in the InAs/GaAsN sublayers goes along with an improved morphology, which is reflected by a decrease of all broadening parameters and by room-temperature photoluminescence emission.

Original languageEnglish (US)
Pages7-12
Number of pages6
StatePublished - Dec 1 2000
Event27th International Symposium on Compound Semiconductors - Monterey, CA, United States
Duration: Oct 2 2000Oct 5 2000

Other

Other27th International Symposium on Compound Semiconductors
CountryUnited States
CityMonterey, CA
Period10/2/0010/5/00

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Optical constants
Superlattices
Photons
Energy gap
Wavelength
Spectroscopic ellipsometry
Alloying
Photoluminescence
Optical properties
Nitrogen
Infrared radiation
Chemical analysis
Temperature

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Leibiger, G., Gottschalch, V., Kasik, A., Rheinländer, B., Ŝik, J., & Schubert, M. (2000). Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices. 7-12. Paper presented at 27th International Symposium on Compound Semiconductors, Monterey, CA, United States.

Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices. / Leibiger, G.; Gottschalch, V.; Kasik, A.; Rheinländer, B.; Ŝik, J.; Schubert, Mathias.

2000. 7-12 Paper presented at 27th International Symposium on Compound Semiconductors, Monterey, CA, United States.

Research output: Contribution to conferencePaper

Leibiger, G, Gottschalch, V, Kasik, A, Rheinländer, B, Ŝik, J & Schubert, M 2000, 'Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices' Paper presented at 27th International Symposium on Compound Semiconductors, Monterey, CA, United States, 10/2/00 - 10/5/00, pp. 7-12.
Leibiger G, Gottschalch V, Kasik A, Rheinländer B, Ŝik J, Schubert M. Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices. 2000. Paper presented at 27th International Symposium on Compound Semiconductors, Monterey, CA, United States.
Leibiger, G. ; Gottschalch, V. ; Kasik, A. ; Rheinländer, B. ; Ŝik, J. ; Schubert, Mathias. / Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices. Paper presented at 27th International Symposium on Compound Semiconductors, Monterey, CA, United States.6 p.
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abstract = "Spectroscopic ellipsometry (SE) is employed to study the optical properties of tensile (compressive) strained GaAs1-yNy(InAs)/GaAs [0{\%} ≤ y ≤ 3.3{\%}] superlattices and GaAs1-yNy [0{\%} ≤ y ≤ 3.7{\%}] single layers for photon energies from 0.75 eV to 4.5 eV and for wavenumbers from 100 cm-1 to 600 cm-1. We provide parametric model functions for the dielectric function spectra of GaAsN in both photon energy ranges. The model functions for photon energies from 0.75 eV to 4.5 eV excellently match dielectric function data obtained from a numerical wavelength-by-wavelength inversion of the experimental data. Critical-point analysis of the ellipsometric data is performed in the spectral regions of the fundamental band gap and the critical points E1 and E1+Δ1. The band-gap energy is red shifted whereas the E1 and E1+Δ1 transition energies are blue shifted with increasing y. For y ≤ 1.65{\%} the observed blue shift of the E1 energy is well explained by the sum of the effects of biaxial (001) strain and alloying. The GaAsN layers show two-mode behaviour in the infrared spectral range (100 cm-1 to 600 cm-1). We detect the transverse GaAs- and GaN- sublattice modes at wavenumbers of about 267 cm-1 and 470 cm-1, respectively. The polar strength of the GaN TO mode increases linearly with y, but with different slopes for the GaAsN/GaAs and GaAsN/InAs/GaAs superlattices, respectively. This is due to the different strain states. This effect can be used to monitor strain or nitrogen composition in GaAsN layers. We further detect free carriers in the GaAsN sublayers of the GaAsN/GaAs superlattices. The absence of free carriers in the InAs/GaAsN sublayers goes along with an improved morphology, which is reflected by a decrease of all broadening parameters and by room-temperature photoluminescence emission.",
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T1 - Optical constants, critical points, free carrier effects, and phonon modes of GaAsN single layers and GaAsN/InAs/GaAs superlattices

AU - Leibiger, G.

AU - Gottschalch, V.

AU - Kasik, A.

AU - Rheinländer, B.

AU - Ŝik, J.

AU - Schubert, Mathias

PY - 2000/12/1

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N2 - Spectroscopic ellipsometry (SE) is employed to study the optical properties of tensile (compressive) strained GaAs1-yNy(InAs)/GaAs [0% ≤ y ≤ 3.3%] superlattices and GaAs1-yNy [0% ≤ y ≤ 3.7%] single layers for photon energies from 0.75 eV to 4.5 eV and for wavenumbers from 100 cm-1 to 600 cm-1. We provide parametric model functions for the dielectric function spectra of GaAsN in both photon energy ranges. The model functions for photon energies from 0.75 eV to 4.5 eV excellently match dielectric function data obtained from a numerical wavelength-by-wavelength inversion of the experimental data. Critical-point analysis of the ellipsometric data is performed in the spectral regions of the fundamental band gap and the critical points E1 and E1+Δ1. The band-gap energy is red shifted whereas the E1 and E1+Δ1 transition energies are blue shifted with increasing y. For y ≤ 1.65% the observed blue shift of the E1 energy is well explained by the sum of the effects of biaxial (001) strain and alloying. The GaAsN layers show two-mode behaviour in the infrared spectral range (100 cm-1 to 600 cm-1). We detect the transverse GaAs- and GaN- sublattice modes at wavenumbers of about 267 cm-1 and 470 cm-1, respectively. The polar strength of the GaN TO mode increases linearly with y, but with different slopes for the GaAsN/GaAs and GaAsN/InAs/GaAs superlattices, respectively. This is due to the different strain states. This effect can be used to monitor strain or nitrogen composition in GaAsN layers. We further detect free carriers in the GaAsN sublayers of the GaAsN/GaAs superlattices. The absence of free carriers in the InAs/GaAsN sublayers goes along with an improved morphology, which is reflected by a decrease of all broadening parameters and by room-temperature photoluminescence emission.

AB - Spectroscopic ellipsometry (SE) is employed to study the optical properties of tensile (compressive) strained GaAs1-yNy(InAs)/GaAs [0% ≤ y ≤ 3.3%] superlattices and GaAs1-yNy [0% ≤ y ≤ 3.7%] single layers for photon energies from 0.75 eV to 4.5 eV and for wavenumbers from 100 cm-1 to 600 cm-1. We provide parametric model functions for the dielectric function spectra of GaAsN in both photon energy ranges. The model functions for photon energies from 0.75 eV to 4.5 eV excellently match dielectric function data obtained from a numerical wavelength-by-wavelength inversion of the experimental data. Critical-point analysis of the ellipsometric data is performed in the spectral regions of the fundamental band gap and the critical points E1 and E1+Δ1. The band-gap energy is red shifted whereas the E1 and E1+Δ1 transition energies are blue shifted with increasing y. For y ≤ 1.65% the observed blue shift of the E1 energy is well explained by the sum of the effects of biaxial (001) strain and alloying. The GaAsN layers show two-mode behaviour in the infrared spectral range (100 cm-1 to 600 cm-1). We detect the transverse GaAs- and GaN- sublattice modes at wavenumbers of about 267 cm-1 and 470 cm-1, respectively. The polar strength of the GaN TO mode increases linearly with y, but with different slopes for the GaAsN/GaAs and GaAsN/InAs/GaAs superlattices, respectively. This is due to the different strain states. This effect can be used to monitor strain or nitrogen composition in GaAsN layers. We further detect free carriers in the GaAsN sublayers of the GaAsN/GaAs superlattices. The absence of free carriers in the InAs/GaAsN sublayers goes along with an improved morphology, which is reflected by a decrease of all broadening parameters and by room-temperature photoluminescence emission.

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