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Hintzsche, L. E.; Fang, Chung; Marsman, Martijn; Jordan, Gerald; Lamers, M.W.P.E.; Weeber, A.W.; Kresse, Georg

doi:10.1103/physrevb.88.155204

Cited by 21 publications

(26 citation statements)

References 45 publications

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“…Shown from the density of states (DOS) in Figure 5, the excess Si in Si-rich silicon nitride SixNy has introduced (i) extra electronic states in the band gap just above the Fermi level which can be assigned to the unsaturated Si bonds; (ii) broader Si nonbonding feature in the range of 5-10 eV at conduction band. This observation is similar to a recent finding of Hintzsche [32] for amorphous SixNyHz. For the Si7N7 cluster, the intensity of the unsaturated Si feature is much smaller and the overall DOS plot is shifted to lower energy.…”

Section: Sixny-the Influence Of the Si/n Ratio And Si Positionssupporting

confidence: 93%

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

et al. 2015

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Abstract:The real and imaginary parts of the complex refractive index of SixNyHz have been calculated from first principles. Optical spectra for reflectivity, absorption coefficient, energy-loss function (ELF), and refractive index were obtained. The results for Si3N4 are in agreement with the available theoretical and experimental results. To understand the electron energy loss mechanism in Si-rich silicon nitride, the influence of the Si/N ratio, the positions of the access Si atoms, and H in and on the surface of the ELF have been investigated. It has been found that all defects, such as dangling bonds in the bulk and surfaces, increase the intensity of the ELF in the low energy range (below 10 eV). H in the bulk and on the surface has a healing effect, which can reduce the intensity of the loss peaks by saturating the dangling bonds. Electronic structure analysis has confirmed the origin of the changes in the ELF. It has demonstrated that the changes in ELF are not only affected by the composition but also by the microstructures of the materials. The results can be used to tailor the optical properties, in this case the ELF of Si-rich Si3N4, which is essential for secondary electron emission applications.

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Section: Sixny-the Influence Of the Si/n Ratio And Si Positionssupporting

confidence: 93%

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

et al. 2015

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“…The GW method, a beyond-DFT approach, is very suitable to describe the excitation processes of sp electrons (a quasi-particle (QP) approach) and has been successfully applied to many systems. 49,50,52,53,70 For example, Hermann and co-workers performed a non-self-consistent G0W0 correction for ice. 31,32 The requirements for computational capability limit us to the Ice-XI phase.…”

Section: Iiid Gw0 Corrections and Comparison With Experimental Obsementioning

confidence: 99%

The accurate calculation of the band gap of liquid water by means of GW corrections applied to plane-wave density functional theory molecular dynamics simulations

Fang

Koster

et al. 2015

Phys. Chem. Chem. Phys.

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Knowledge about the intrinsic electronic properties of water is imperative for understanding the behaviour of aqueous solutions that are used throughout biology, chemistry, physics, and industry. The calculation of the electronic band gap of liquids is challenging, because the most accurate ab initio approaches can be applied only to small numbers of atoms, while large numbers of atoms are required for having configurations that are representative of a liquid. Here we show that a high-accuracy value for the electronic band gap of water can be obtained by combining beyond-DFT methods and statistical time-averaging. Liquid water is simulated at 300 K using a plane-wave density functional theory molecular dynamics (PW-DFT-MD) simulation and a van der Waals density functional (optB88-vdW).After applying a self-consistent GW correction the band gap of liquid water at 300 K is calculated as 7.3 eV, in good agreement with recent experimental observations in the literature (6.9 eV). For simulations of phase transformations and chemical reactions in water or aqueous solutions whereby an accurate description of the electronic structure is required, we suggest to use these advanced GW corrections in combination with the statistical analysis of quantum mechanical MD simulations.

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“…We also performed simulations for selected systems with the pinned O method for sake of comparison. We employed the time-averaged method for sampling the interfaces over a period of time, typically 3.0 ps to 4.5 ps to provide statistically meaningful results [40,48].…”

Section: Computational Settingsmentioning

confidence: 99%

Prenucleation at the liquid-Al/α-Al2O3 and the liquid-Al/MgO interfaces

Fang

Fan

2020

Computational Materials Science

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Prenucleation refers to the atomic ordering in the liquid adjacent to a liquid/substrate interface above the nucleation temperature. It provides a precursor for heterogeneous nucleation in the liquid adjacent to the interface. As magnesia (MgO) and alumina (Al 2 O 3) widely exist in and can be potential nucleation sites for Al-Mg based alloys, we investigate the influences of the substrate surfaces, the α-Al 2 O 3 {0 0 0 1} and the Al-terminated MgO{1 1 1} on the atomic ordering in the liquid Al adjacent to the liquid-Al/oxide interfaces using an ab initio molecular dynamics simulation technique. The study reveals the formation of an Al-layer terminating the substrates. The newly formed Al-layers display structural splitting and possess atomic vacancies, being atomically rough. Consequently, there is weak prenucleation at the liquid/oxide interfaces. Analysis also exposes subtle influences of the structural and chemical properties of the oxide substrates on the prenucleation at the interfaces. The attained information sheds light on the role of oxide particles in the solidification of Al-Mg based alloys.

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Defects and defect healing in amorphous Si3N4−xHy:

Cited by 21 publications

References 45 publications

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

Optical Properties of Silicon-Rich Silicon Nitride (SixNyHz) from First Principles

The accurate calculation of the band gap of liquid water by means of GW corrections applied to plane-wave density functional theory molecular dynamics simulations

Prenucleation at the liquid-Al/α-Al2O3 and the liquid-Al/MgO interfaces

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