Surface exciton emission of MgO crystals

Kuang, Wenjian; Li, Qing; Chen, Yuxiang; Hu, Kai; Wang, Ninghui; Xing, Fang-Li; Yan, Qun; Sun, Shuaishuai; Huang, Yan; Ye, Tao; Tolner, Harm

doi:10.1088/0022-3727/46/36/365501

Cited by 11 publications

(9 citation statements)

References 27 publications

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“…Additional experimental results are needed, especially using synchrotron excitation and fluorescence emission detection, as a function of temperature, similar to those obtained for doped MgO [34].…”

Section: Discussionmentioning

confidence: 96%

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

et al. 2016

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In this work, the electronic structure and optical properties of Mg 1−x Zn x O (0 ≤ x ≤ 0.5) are investigated within the framework of the density functional theory (DFT), the GW method, and the Bethe-Salpeter equation (BSE). We find that zinc doping can lower the band gap of pure MgO via the Zn 4s states near the Fermi level and reduce the lattice symmetry, both of which will affect the optical properties. The energy of the first absorption peak decreases as the concentration of zinc increases, so are the exciton energy and binding energy of the lowest excited state. The results nicely fit to published experimental results and are compared to those of the simple hydrogen-like atom model for excitons. As the lowest excited state is closely related to light emission at that energy according to Kasha's rule, zinc doping will lower the light emission energy of pure MgO, while still exhibiting an exciton binding energy much higher than that of k B T at room temperature. This means that Mg 1−x Zn x O materials are perfectly suited for optoelectronic devices operating in the deep blue and near-ultraviolet (UV) range.

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Section: Discussionmentioning

confidence: 96%

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

et al. 2016

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“…The dark excitons are of special interest for PDPs, as they do not decay radiatively, but instead release their energy mainly by Auger electron emission through exciton–electron or exciton–exciton interactions . As dark excitons are triplet states, the lifetime is relatively long, and therefore, they could play a role in the delayed electron emission, observed in MgO after plasma bombardment in a PDP …”

Section: Resultsmentioning

confidence: 99%

“…To date, MgCaO solid solutions have been fabricated by various methods . Some of the UV emission and excitation properties have been measured and investigated . However, the bandgap reduction as a function of increased calcium content and the related optical properties of Mg 1 − x Ca x O are not clear.…”

Section: Introductionmentioning

confidence: 99%

“…12 Some of the UV emission and excitation properties have been measured and investigated. 13 However, the bandgap reduction as a function of increased calcium content and the related optical properties of Mg 1 À x Ca x O are not clear. Furthermore, calculated optical properties considering electron-hole interaction have only been published 14,15 for either MgO or CaO, but not for the important mixed phase.…”

Section: Introductionmentioning

confidence: 99%

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Deep‐UV exciton emission from Mg_1 − xCa_xO—A first‐principle investigation

Yan

Yang

et al. 2014

J Soc Info Display

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-In order to investigate the ultraviolet and electron emission properties of rock-salt Mg 1 À x Ca x O, first-principle calculations are carried out with x ranging from 0 to 0.5. The electronhole interaction is taken into account by solving the Bethe-Salpeter equation. In pure MgO, the calculated exciton binding-energy value of 83 ± 3 meV is quite close to the published experimental values. The electronic properties of doped MgO are investigated based on the super-cell model. Both the optical bandgap and the exciton binding energy of the super cell of Mg 1 À x Ca x O are calculated for five discrete compositions, with an increasing amount x of CaO. The results show that there are strong excitonic effects in all of these materials. A rapid reduction in bandgap value is observed for Mg 1 À x Ca x O, when increasing the x value. The exciton binding energy of Mg 1 À x Ca x O shows a minimum value of about 40 meV around x = 0.2. In all of these cases, the exciton is stable at room temperature. The lowest excitation levels in Mg 1 À x Ca x O are determined by dark excitons. The occurrence of these dark excitons might explain why Mg 1 À x Ca x O is a strong source of delayed electron emission, after being bombarded by ions in a plasma.

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“…[10]- [12] The large value of the exciton binding energy of MgO (80 meV) and small radius (1.5 nm) is advantageous for an efficient transport of excitons. [13]- [15] The bottom of the conduction-band of MgO crystals is located around the vacuum energy (depending on the references, the electron affinity is stated as either positive or negative). [16]- [19] This is supposed to balance the injection of electrons and holes by impeding electron injection.…”

Section: Introductionmentioning

confidence: 99%

Optical Properties of Ultraviolet Quantum Dot Light-Emitting Devices Using ZnO-Cores With a MgO-Shell

Kuang

Pan

et al. 2015

J. Display Technol.

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Colloidal quantum dots with a ZnO core were synthesized with subsequent surface passivation by MgO. The photo-enhancement effect of the near band-edge photoluminescence in ZnO nanocrystals, dispersed in ethanol, is investigated by observing changes in the optical properties after ultraviolet (UV) exposure. Finally the operation as a light-emitting device (LED) was demonstrated experimentally for these ZnO-based quantum dots (QDs). The results indicate that this type of QDs might enable the development of electroluminescent UV sources in the near future. Index Terms-Quantum dots, ZnO, MgO, ultraviolet, photoluminescence, electroluminescent, nanocrystals 1551-319X (c)

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Surface exciton emission of MgO crystals

Cited by 11 publications

References 27 publications

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

Deep‐UV exciton emission from Mg_1 − xCa_xO—A first‐principle investigation

Optical Properties of Ultraviolet Quantum Dot Light-Emitting Devices Using ZnO-Cores With a MgO-Shell

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Surface exciton emission of MgO crystals

Cited by 11 publications

References 27 publications

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

Theoretical investigation of the electronic structure and optical properties of zinc-doped magnesium oxide

Deep‐UV exciton emission from Mg1 − xCaxO—A first‐principle investigation

Optical Properties of Ultraviolet Quantum Dot Light-Emitting Devices Using ZnO-Cores With a MgO-Shell

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Deep‐UV exciton emission from Mg_1 − xCa_xO—A first‐principle investigation