Optical properties of wurtzite structure GaN on sapphire around fundamental absorption edge (0.78-4.77 eV) by spectroscopic ellipsometry and the optical transmission method

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

Research output: Contribution to journalArticle

223 Citations (Scopus)

Abstract

Spectroscopic ellipsometry (SE) together with the optical transmission method is successfully used to determine the refractive index n and absorption coefficient α of undoped gallium nitride film over the spectral range of 0.78-4.77 eV of photon energy. The SE measurement is carried out at angle of incidence of 60° over the 1.5-4.77 eV energy range and optical transmission measurement over the 0.78-3.55 eV energy range. The refractive index n and absorption coefficient α obtained by both methods show unique results in the overlap wavelength region. Refractive index n is found to follow the Sellmeir dispersion relationship n2(λ)=2.272+304.72/(λ 2-294.02) below the fundamental band edge. A free excitonic structure at the band is clearly observed at room temperature, with the transmission energy of free exciton at 3.44 eV, which is in reasonable agreement with the reported results.

Original languageEnglish
Pages (from-to)3209-3211
Number of pages3
JournalApplied Physics Letters
Volume70
Issue number24
Publication statusPublished - 1997 Jun 16
Externally publishedYes

Fingerprint

wurtzite
ellipsometry
sapphire
optical properties
refractivity
absorptivity
energy
gallium nitrides
coefficients
incidence
excitons
photons
room temperature
wavelengths

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Optical properties of wurtzite structure GaN on sapphire around fundamental absorption edge (0.78-4.77 eV) by spectroscopic ellipsometry and the optical transmission method. / Yu, G.; Wang, G.; Ishikawa, H.; Umeno, M.; Soga, T.; Egawa, T.; Watanabe, J.; Jimbo, T.

In: Applied Physics Letters, Vol. 70, No. 24, 16.06.1997, p. 3209-3211.

Research output: Contribution to journalArticle

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abstract = "Spectroscopic ellipsometry (SE) together with the optical transmission method is successfully used to determine the refractive index n and absorption coefficient α of undoped gallium nitride film over the spectral range of 0.78-4.77 eV of photon energy. The SE measurement is carried out at angle of incidence of 60° over the 1.5-4.77 eV energy range and optical transmission measurement over the 0.78-3.55 eV energy range. The refractive index n and absorption coefficient α obtained by both methods show unique results in the overlap wavelength region. Refractive index n is found to follow the Sellmeir dispersion relationship n2(λ)=2.272+304.72/(λ 2-294.02) below the fundamental band edge. A free excitonic structure at the band is clearly observed at room temperature, with the transmission energy of free exciton at 3.44 eV, which is in reasonable agreement with the reported results.",
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AU - Yu, G.

AU - Wang, G.

AU - Ishikawa, H.

AU - Umeno, M.

AU - Soga, T.

AU - Egawa, T.

AU - Watanabe, J.

AU - Jimbo, T.

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AB - Spectroscopic ellipsometry (SE) together with the optical transmission method is successfully used to determine the refractive index n and absorption coefficient α of undoped gallium nitride film over the spectral range of 0.78-4.77 eV of photon energy. The SE measurement is carried out at angle of incidence of 60° over the 1.5-4.77 eV energy range and optical transmission measurement over the 0.78-3.55 eV energy range. The refractive index n and absorption coefficient α obtained by both methods show unique results in the overlap wavelength region. Refractive index n is found to follow the Sellmeir dispersion relationship n2(λ)=2.272+304.72/(λ 2-294.02) below the fundamental band edge. A free excitonic structure at the band is clearly observed at room temperature, with the transmission energy of free exciton at 3.44 eV, which is in reasonable agreement with the reported results.

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