Band gaps, crystal-field splitting, spin-orbit coupling, and exciton binding energies in ZnO under hydrostatic pressure

Mang, A.; Reimann, K.; Rübenacke, St.

doi:10.1016/0038-1098(95)00054-2

Cited by 503 publications

(237 citation statements)

References 23 publications

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“…states. Though these selections rules may be modified due to, e.g., strong admixture of dstates to the VB states that is the case for ZnO [34], the oscillator strength of TPA for the S excitons in bulk ZnO remains very low [32]. Our results show that the same selection rules also apply to nanostructured ZnO.…”

Section: Energy Upconversion: Two Photon Absorptionsupporting

confidence: 52%

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

et al. 2012

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Abstract.Efficient upconversion of photoluminescence (PL) from donor bound excitons is revealed in bulk and nanorod ZnO. Based on excitation power dependent PL measurements performed with different energies of excitation photons, two-photon-absorption (TPA) and two-step TPA (TS-TPA) processes are concluded to be responsible for the upconversion. The TS-TPA process is found to occur via a defect/impurity (or defects/impurities) with an energy level (or levels) lying within 1.14-1.56 eV from one of the band edges, without involving photon recycling. One of the possible defect candidates could be V Zn . A sharp energy threshold, different from that for the corresponding one-photon absorption, is observed for the TPA process and is explained in terms of selection rules for the involved optical transitions.

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Section: Energy Upconversion: Two Photon Absorptionsupporting

confidence: 52%

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

et al. 2012

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“…These states correspond to A, B, and C exciton lines in photoluminescence experiments. 54 The symmetry of two of these three bands are of Γ 7 character and one of Γ 9 character. The Γ 7 state derived from Γ 5…”

Section: Resultsmentioning

confidence: 99%

Coulomb correlation effects in zinc monochalcogenides

Karazhanov

Ravindran

Großner

et al. 2006

Journal of Applied Physics

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Electronic structure and band characteristics for zinc monochalcogenides with zinc-blende-and wurtzite-type structures are studied by first-principles density-functional-theory calculations with different approximations. It is shown that the local-density approximation underestimates the band gap and energy splitting between the states at the top of the valence band, misplaces the energy levels of the Zn-3d states, and overestimates the crystal-field-splitting energy. The spin-orbit-coupling energy is found to be overestimated for both variants of ZnO, underestimated for ZnS with wurtzitetype structure, and more or less correct for ZnSe and ZnTe with zinc-blende-type structure. The order of the states at the top of the valence band is found to be anomalous for both variants of ZnO, but is normal for the other zinc monochalcogenides considered. It is shown that the Zn-3d electrons and their interference with the O-2p electrons are responsible for the anomalous order. The effective masses of the electrons at the conduction-band minimum and of the holes at the valence-band maximum have been calculated and show that the holes are much heavier than the conduction-band electrons in agreement with experimental findings. The calculations, moreover, indicate that the effective masses of the holes are much more anisotropic than the electrons. The typical errors in the calculated band gaps and related parameters for ZnO originate from strong Coulomb correlations, which are found to be highly significant for this compound. The local-density-approximation with multiorbital mean-field Hubbard potential approach is found to correct the strong correlation of the Zn-3d electrons, and thus to improve the agreement between the experimentally established location of the Zn-3d levels and that derived from pure LDA calculations.

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“…The observed band gaps of these systems appear in the range of wide band gap semiconductors and these values are even more than the band gap of ZnO (3.37 eV) and GaN (3.44 eV). [43][44][45] In addition, these systems show much better magnetic ordering and magnetic moment 46 than any known diluted magnetic semiconductors, which might prove significant in applications as magnetic semiconductors. The absorption coefficient near the band edge decays exponentially with photon energy (Fig.…”

Section: Ultraviolet-visible Spectroscopymentioning

confidence: 99%

Structural, transport and optical properties of (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃nanocrystals: a wide band-gap magnetic semiconductor

et al. 2015

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Band gaps, crystal-field splitting, spin-orbit coupling, and exciton binding energies in ZnO under hydrostatic pressure

Cited by 503 publications

References 23 publications

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

Coulomb correlation effects in zinc monochalcogenides

Structural, transport and optical properties of (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃nanocrystals: a wide band-gap magnetic semiconductor

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Band gaps, crystal-field splitting, spin-orbit coupling, and exciton binding energies in ZnO under hydrostatic pressure

Cited by 503 publications

References 23 publications

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

Efficient upconversion of photoluminescence via two-photon absorption in bulk and nanorod ZnO

Coulomb correlation effects in zinc monochalcogenides

Structural, transport and optical properties of (La0.6Pr0.4)0.65Ca0.35MnO3nanocrystals: a wide band-gap magnetic semiconductor

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Structural, transport and optical properties of (La_0.6Pr_0.4)_0.65Ca_0.35MnO₃nanocrystals: a wide band-gap magnetic semiconductor