Band Structure and Reflectivity of GaN

Bloom, S.; Harbeke, G.; Meier, Edi; Ortenburger, Irene B.

doi:10.1002/pssb.2220660117

Cited by 165 publications

(44 citation statements)

References 18 publications

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“…1, are closer to the experimental results of AlN and GaN. 34 It is further noted that our theoretical results are much improved over those previously published. 19 The reason for our better results is the effectiveness of Wu-Cohen potential in the GGA scheme.…”

Section: Resultssupporting

confidence: 87%

Ab initio study of the bandgap engineering of Al1−xGaxN for optoelectronic applications

Amin¹,

Ahmad²,

Maqbool³

et al. 2011

Journal of Applied Physics

181

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A theoretical study of Al 1−x Ga x N, based on the full-potential linearized augmented plane wave method, is used to investigate the variations in the bandgap, optical properties, and nonlinear behavior of the compound with the change in the Ga concentration. It is found that the bandgap decreases with the increase in Ga. A maximum value of 5.50 eV is determined for the bandgap of pure AlN, which reaches a minimum value of 3.0 eV when Al is completely replaced by Ga. The static index of refraction and dielectric constant decreases with the increase in the bandgap of the material, assigning a high index of refraction to pure GaN when compared to pure AlN. The refractive index drops below 1 for higher energy photons, larger than 14 eV. The group velocity of these photons is larger than the vacuum velocity of light. This astonishing result shows that at higher energies the optical properties of the material shifts from linear to nonlinear. Furthermore, frequency dependent reflectivity and absorption coefficients show that peak values of the absorption coefficient and reflectivity shift toward lower energy in the ultraviolet ͑UV͒ spectrum with the increase in Ga concentration. This comprehensive theoretical study of the optoelectronic properties predicts that the material can be effectively used in the optical devices working in the visible and UV spectrum.

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Section: Resultssupporting

confidence: 87%

Ab initio study of the bandgap engineering of Al1−xGaxN for optoelectronic applications

Amin¹,

Ahmad²,

Maqbool³

et al. 2011

Journal of Applied Physics

181

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“…[7] [9] [10] [11] [16] [17], the order of levels in the valence band of the nitrides is different: in GaN and InN, Γ 6 branch lies above Γ 1 , whereas in AlN it lies below Γ 1 . The symmetry of the electron wave functions in different bands and band branches leads to the following selection rules for the radiative transitions:…”

Section: Energy Spectra Of the Nitride Semiconductorsmentioning

confidence: 99%

The Rate of Radiative Recombination in the Nitride Semiconductors and Alloys

Dmitriev

Oruzheinikov

1996

MRS Internet j. nitride semicond. res.

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The radiative recombination rates have been calculated for the first time in the wide band gap wurtzite semiconductors GaN, InN and AlN and their solid solutions Ga x Al 1-x N and In x Al 1-x N on the base of existing data on the energy band structure and optical absorption in these materials. We calculated the interband matrix elements for the direct optical transitions between the conductivity band and the valence one using the experimental photon energy dependence of the absorption coefficient near the band edge. In our calculations we assumed that the material parameters of the solid solutions (the interband matrix element, carrier effective masses and so on) could be obtained by a linear interpolation between their values in the alloy components. The temperature dependence of the energy gap was taken in the form proposed by Varshni. The calculations of the radiative recombination rates were performed in the wide range of temperature and alloy compositions.

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“…Numerous band structure calculations have been performed. [6][7][8][9][10][11] They have been compared with optical measurements 12 and limited photoemission spectroscopy measurements. [13][14][15][16][17][18][19] There have as yet been no systematic measurements on surfaces of GaN that are believed to be clean.…”

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confidence: 99%