Synchrotron-based photoluminescence excitation spectroscopy applied to investigate the valence band splittings in AlN and Al0.94Ga0.06N

Feneberg, Martin; Röppischer, Marcus; Esser, N.; Cobet, Christoph; Neuschl, Benjamin; Meisch, Tobias; Thonke, Klaus; Goldhahn, R.

doi:10.1063/1.3610469

Cited by 7 publications

(12 citation statements)

References 20 publications

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“…2, for example). As c-plane 56,71 , where Δ CF is VB crystal-field splitting. It separates the uppermost valence subband of c-plane AlN, transitions from which to its CB are forbidden when excited by light with E ⊥ c (normal incidence of light), from those for which such transitions are allowed.…”

Section: Modified the Iliopoulos Et Al Formula And Proposed The New mentioning

confidence: 99%

Bandgap and refractive index estimates of InAlN and related nitrides across their full composition ranges

Alam¹,

Zubialevich²,

Ghafary

et al. 2020

Sci Rep

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III-Nitride bandgap and refractive index data are of direct relevance for the design of (In, Ga, Al)N-based photonic and electronic devices. The bandgaps and bandgap bowing parameters of III-nitrides across the full composition range are reviewed with a special emphasis on InxAl1−xN, where less consensus was reached in the literature previously. Considering the available InAlN data, including those recently reported for low indium contents, empirical formulae for InAlN bandgap and bandgap bowing parameter are proposed. Applying the generalised bandgap data, the refractive index dispersion data available in the literature for III-N alloys is fitted using the Adachi model. For this purpose, a formalism involving a parabolic dependence of the Adachi parameters on the dimensionless bandgap $${\xi }_{{E}_{\mathrm{g}}}=\left({E}_{\mathrm{g}, {\mathrm{A}}_{x}{\mathrm{B}}_{1-x}\mathrm{N}}-{E}_{\mathrm{g},\mathrm{ BN}}\right)/\left({E}_{\mathrm{g}, \mathrm{AN}}-{E}_{\mathrm{g},\mathrm{ BN}}\right)$$ ξ E g = E g , A x B 1 - x N - E g , BN / E g , AN - E g , BN of the corresponding ternary alloys is used rather than one directly invoking the alloy composition.

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Section: Modified the Iliopoulos Et Al Formula And Proposed The New mentioning

confidence: 99%

Bandgap and refractive index estimates of InAlN and related nitrides across their full composition ranges

Alam¹,

Zubialevich²,

Ghafary

et al. 2020

Sci Rep

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“…NEXAS has been successfully applied to large biological systems, 2 small molecules in the gas phase, 3 organic thin-films, 4 and semiconducting materials. 5 This wide range of applications is possible because synchrotron light sources can span an energy range that goes from a few electron volt (eV) 6 to hundreds of MeV. 7 …”

Section: Introductionmentioning

confidence: 99%

Simulation of X-ray absorption spectra with orthogonality constrained density functional theory

Derricotte

Evangelista

2015

Phys. Chem. Chem. Phys.

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Orthogonality constrained density functional theory (OCDFT) is a variational time-independent approach for the computation of electronic excited states. In this work we extend OCDFT to compute core-excited states and generalize the original formalism to determine multiple excited states. Benchmark computations on a set of 13 small molecules and 40 excited states show that unshifted OCDFT/B3LYP excitation energies have a mean absolute error of 1.0 eV. Contrary to time-dependent DFT, OCDFT excitation energies for first- and second-row elements are computed with near-uniform accuracy. OCDFT core excitation energies are insensitive to the choice of the functional and the amount of Hartree–Fock exchange. We show that OCDFT is a powerful tool for the assignment of X-ray absorption spectra of large molecules by simulating the gas-phase near-edge spectrum of adenine and thymine.

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“…An overview is given in Fig. 9, where we compare data at T = 10 K. The DFs were used to calculate an unpolarized reflectivity for normal-incidence light, 61 which is in turn compared to experimental data measured with a D 2 lamp as an unpolarized light source under normal incidence and with synchrotron radiation under slanted incidence of light. The PL spectrum and a PLE spectrum (using a weak low-energy defect luminescence band as a monitor) are displayed as well.…”

Section: Emission Propertiesmentioning

confidence: 99%

Anisotropic absorption and emission of bulk(11¯00)AlN

et al. 2013

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The intrinsic anisotropic optical properties of wurtzite AlN are investigated in absorption and emission. Full access to the anisotropy of the optical response of the hexagonal material is obtained by investigating the (1100) plane of a high-quality bulk crystal allowing electric field E polarization perpendicular (E ⊥ c) and parallel (E c) to the optical axis c. Spectroscopic ellipsometry yields the ordinary (ε ⊥ ) and extraordinary (ε ) dielectric functions (DFs) from 0.58 up to 20 eV. The comparison of the experimental data with recently calculated DFs demonstrates that Coulomb interaction has a strong impact not only on the spectral dependence around the fundamental absorption edge but also on the high-energy features usually discussed in terms of van Hove singularities. The fits of the second-order derivatives of ε and ε ⊥ provide the transition energies for the main features in this range. The DFs close to the fundamental absorption edge, dominated by free excitons, exciton-phonon complexes, and the exciton continuum, are independently confirmed by reflectivity and synchrotron-based photoluminescence excitation studies. Values for the band gaps, the crystal field ( cf = −221 ± 2 meV), and spin-orbit splittings ( so = 13 ± 2 meV) are obtained. Furthermore, we obtain accurate values for the static dielectric constants of ε S⊥ = 7.65 and ε S = 9.21, entering, e.g., the calculations of exciton binding energies. Photoluminescence is used to investigate the emission properties of the same sample.

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Synchrotron-based photoluminescence excitation spectroscopy applied to investigate the valence band splittings in AlN and Al0.94Ga0.06N

Cited by 7 publications

References 20 publications

Bandgap and refractive index estimates of InAlN and related nitrides across their full composition ranges

Bandgap and refractive index estimates of InAlN and related nitrides across their full composition ranges

Simulation of X-ray absorption spectra with orthogonality constrained density functional theory

Anisotropic absorption and emission of bulk(11¯00)AlN

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