Optical properties of AlxGa1-xN/GaN heterostructures on sapphire by spectroscopic ellipsometry

G. Yu; H. Ishikawa; M. Umeno; T. Egawa; J. Watanabe; T. Jimbo; T. Soga

doi:10.1063/1.121322

Optical properties of Al_xGa_1-xN/GaN heterostructures on sapphire by spectroscopic ellipsometry

G. Yu, H. Ishikawa, M. Umeno, T. Egawa, J. Watanabe, T. Jimbo, T. Soga

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

63 Citations (Scopus)

Abstract

A method of analysis of spectroscopic ellipsometry (SE) measurement data is proposed for Al_xGa_1-xN/GaN heterostructures grown on sapphire substrates. The SE data measured at three angles of incidence, 40°, 50°, and 60°, are simultaneously fitted assuming the dielectric function to consist of a Sellmeir dispersion equation and a free-exciton absorption term. The refractive index n and the extinction coefficient k of undoped Al_xGa_1-xN films are determined in the spectral range of 1.5-4.13 eV of photon energy. The transition energy of the free exciton, which is in excellent agreement with the reported results for GaN in a previous paper, is found to vary from 3.44 to 3.95 eV when the composition x varies from 0 to 0.151. The refractive index n of Al_xGa_1-xN has also been compared with those reported results.

Original language	English
Pages (from-to)	2202-2204
Number of pages	3
Journal	Applied Physics Letters
Volume	72
Issue number	18
DOIs	https://doi.org/10.1063/1.121322
Publication status	Published - 1998
Externally published	Yes

ASJC Scopus subject areas

Physics and Astronomy (miscellaneous)

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10.1063/1.121322

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title = "Optical properties of AlxGa1-xN/GaN heterostructures on sapphire by spectroscopic ellipsometry",

abstract = "A method of analysis of spectroscopic ellipsometry (SE) measurement data is proposed for AlxGa1-xN/GaN heterostructures grown on sapphire substrates. The SE data measured at three angles of incidence, 40°, 50°, and 60°, are simultaneously fitted assuming the dielectric function to consist of a Sellmeir dispersion equation and a free-exciton absorption term. The refractive index n and the extinction coefficient k of undoped AlxGa1-xN films are determined in the spectral range of 1.5-4.13 eV of photon energy. The transition energy of the free exciton, which is in excellent agreement with the reported results for GaN in a previous paper, is found to vary from 3.44 to 3.95 eV when the composition x varies from 0 to 0.151. The refractive index n of AlxGa1-xN has also been compared with those reported results.",

author = "G. Yu and H. Ishikawa and M. Umeno and T. Egawa and J. Watanabe and T. Jimbo and T. Soga",

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T1 - Optical properties of AlxGa1-xN/GaN heterostructures on sapphire by spectroscopic ellipsometry

AU - Yu, G.

AU - Ishikawa, H.

AU - Umeno, M.

AU - Egawa, T.

AU - Watanabe, J.

AU - Jimbo, T.

AU - Soga, T.

PY - 1998

Y1 - 1998

N2 - A method of analysis of spectroscopic ellipsometry (SE) measurement data is proposed for AlxGa1-xN/GaN heterostructures grown on sapphire substrates. The SE data measured at three angles of incidence, 40°, 50°, and 60°, are simultaneously fitted assuming the dielectric function to consist of a Sellmeir dispersion equation and a free-exciton absorption term. The refractive index n and the extinction coefficient k of undoped AlxGa1-xN films are determined in the spectral range of 1.5-4.13 eV of photon energy. The transition energy of the free exciton, which is in excellent agreement with the reported results for GaN in a previous paper, is found to vary from 3.44 to 3.95 eV when the composition x varies from 0 to 0.151. The refractive index n of AlxGa1-xN has also been compared with those reported results.

AB - A method of analysis of spectroscopic ellipsometry (SE) measurement data is proposed for AlxGa1-xN/GaN heterostructures grown on sapphire substrates. The SE data measured at three angles of incidence, 40°, 50°, and 60°, are simultaneously fitted assuming the dielectric function to consist of a Sellmeir dispersion equation and a free-exciton absorption term. The refractive index n and the extinction coefficient k of undoped AlxGa1-xN films are determined in the spectral range of 1.5-4.13 eV of photon energy. The transition energy of the free exciton, which is in excellent agreement with the reported results for GaN in a previous paper, is found to vary from 3.44 to 3.95 eV when the composition x varies from 0 to 0.151. The refractive index n of AlxGa1-xN has also been compared with those reported results.

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JF - Applied Physics Letters

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ER -

Optical properties of Al_xGa_1-xN/GaN heterostructures on sapphire by spectroscopic ellipsometry

Abstract

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