Luminescence in thermochemically reduced MgO: The role of hydrogen

Jeffries, B. T.; González, R.; Chen, Y.; Summers, G.P.

doi:10.1103/physrevb.25.2077

Cited by 57 publications

(31 citation statements)

References 11 publications

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“…Thus, the excited F + centres can easily promote electrons to the conduction band, forming thereby F 2 + defect centres. These electrons may also be trapped by H À species (usually present due to retained or adsorbed moisture) and having energy levels close to the conduction band edge [15,40,[49][50][51]. Since the energy difference of these species is small, electrons can move via trap-to-trap hopping even at room temperature.…”

Section: Air Ambientmentioning

confidence: 99%

Sol–gel synthesis of highly luminescent magnesium oxide nanocrystallites

Кумар

Thota

Varma

et al. 2011

Journal of Luminescence

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Section: Air Ambientmentioning

confidence: 99%

Sol–gel synthesis of highly luminescent magnesium oxide nanocrystallites

Кумар

Thota

Varma

et al. 2011

Journal of Luminescence

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“…The F-center defect (oxygen vacancy) in MgO is a typical example of an intrinsic point defect in a binary ionic compound [22][23][24][25][26][27]. Despite its apparent simplicity, its properties as deduced from optical absorption and luminescence studies have proven somewhat ambiguous.…”

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confidence: 99%

Point-defect optical transitions and thermal ionization energies from quantum Monte Carlo methods: Application to theF-center defect in MgO

2013

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We present an approach to calculation of point defect optical and thermal ionization energies based on the highly accurate quantum Monte Carlo methods. The use of an inherently many-body theory that directly treats electron correlation offers many improvements over the typically-employed density functional theory Kohn-Sham description. In particular, the use of quantum Monte Carlo methods can help overcome the band gap problem and obviate the need for ad-hoc corrections. We demonstrate our approach to the calculation of the optical and thermal ionization energies of the F-center defect in magnesium oxide, and obtain excellent agreement with experimental and/or other high-accuracy computational results.From electronics to optoelectronics to photovoltaics, point defects influence and even dominate the properties of semiconducting materials [1][2][3][4][5][6]. Quantitative descriptions of the effect of point defects on electronic, optical, and transport properties is critical to enabling point-defect engineering for materials design. However, accurate prediction of point-defect energetics, thermal ionization energies, and optical transition energies from first principles remains a challenge. Currently, the most widely-used approach based on conventional density functional theory (DFT) suffers from poor descriptions of band gaps that render difficult the accurate description of mid-gap defect states [5,[7][8][9]]. Here we demonstrate that, by contrast, an inherently many-body approach based on quantum Monte Carlo (QMC) methods [10,11] can eliminate these problems and enable high-accuracy calculations of point defect optical and thermal ionization energies. Our computed optical transition energies are in excellent agreement with experimental and/or other highaccuracy computational results for the same system [12], and demonstrate that QMC can obtain quantitatively accurate descriptions.

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“…MgO : H crystals, after very strong thermochemical reduction, exhibit an intense emission at 2.3 eV that is long-lived with a lifetime of the Bright-field electron micrograph taken under kinematical diffraction conditions of a Li-doped specimen after annealing for 1 h at 1473 K in flowing oxygen and subsequently annealed in graphite for 1 h at 1473 K. The arrow length is 0 5 pm. order of minutes (Jeffries et al 1982 . 12).…”

Section: Lithium-doped Mgomentioning

confidence: 99%

“…The maximum concentration of these isotopes in oxides can be estimated as of the order of 10" ~m -~. Also the diffusion coefficients at high temperatures are very low compared to those in ceramics (Johnson, Paek and De Ford 1975, Fowler, Chandra, Elleman, Payne and Verghesse 1977, Bates, Wang and Perkins 1979, Engstrom, Bates and Boatner 1980. Engstmm.…”

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confidence: 98%

“…For example, thermochemically reduced crystalline oxides containing isolated oxygen vacancies are ideal candidates as hosts for tunable lasers because these vacancies are thermally stable and emit broad-wavelength luminescence with high quantum efficiencies (Jeffries, Gonzalez, Chen and Summers 1982, Summers, Wilson, Jeffries, Tohver, Chen and Abraham 1983. However, the lifetimes of the luminescence are too long, as exhibited by MgO, CaO and A1,0, crystals.…”

mentioning

confidence: 99%

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