Ab initio study of oxygen segregation in silicon grain boundaries: The role of strain and vacancies

Maji, Rita; Luppi, E.; Capron, Nathalie; Degoli, Elena

doi:10.1016/j.actamat.2020.11.019

Cited by 17 publications

(41 citation statements)

References 53 publications

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“…The formation energy of the vacancy V1 in the GB is E f VGB = 2.91 eV while for the vacancy V2 we found E f VGB = 3.04 eV. [31] The presence of the vacancy induces coordination defects, and in the case of V1 and V2 we have two Si atoms that are threefold coordinated while all the other Si atoms are fourfold coordinated. [10,16,31,[34][35][36] To study the role of C, N and O segregation we then inserted these atoms as interstitials in the Si GB with and without vacancies.…”

Section: Grain Boundary Structuresmentioning

confidence: 80%

“…These structures, without impurities, present a sharp peak at the bottom of the conduction band which, by the analysis of the projected-DOS (not shown), is due to the threefold coordinated atoms Si1 and Si2. [31] Another peak is also observed at around -0.5 eV in the valence band. This peak is due to four coordinated Si atoms but which undergo structural changes due to the presence of the vacancy in the GB.…”

Section: B Carbon Oxygen and Nitrogen Atoms In σ3{111} Si Gb With Vac...mentioning

confidence: 96%

“…The lattice parameters are a=13.30 Å, b=7.68 Å and c=18.81 Å. [31] The formation energy of the Σ3{111} Si GB is E f GB = 0.002 eV/ Å2 (E f GB = 0.05 J/m 2 ) [31] which indicates that this GB has a very regular structure, i.e. bond lengths and angles are close to the Si bulk.…”

Section: Grain Boundary Structuresmentioning

confidence: 99%

“…There exists only two distinct positions of Si where vacancies can be created. [31] These vacancies are indicated throughout the paper as V1 and V2 and are shown respectively in panel (c) and (d) of Fig. 1.…”

Section: Grain Boundary Structuresmentioning

confidence: 99%

“…[31] The presence of the vacancy induces coordination defects, and in the case of V1 and V2 we have two Si atoms that are threefold coordinated while all the other Si atoms are fourfold coordinated. [10,16,31,[34][35][36] To study the role of C, N and O segregation we then inserted these atoms as interstitials in the Si GB with and without vacancies. Different configurations were found and in Figs.…”

Section: Grain Boundary Structuresmentioning

confidence: 99%

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The role of Si vacancies in the segregation of O, C, and N at silicon grain boundaries: An ab initio study

Maji,

Contreras-García,

Capron

et al. 2022

Preprint

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Grain boundaries (GBs) are defects originating in multi-crystalline silicon during crystal growth for device Si solar cell fabrication. The presence of GBs changes the coordination of Si making advantageous for charge carriers to recombine which brings a significant reduction of carrier lifetimes. Therefore, GBs can be highly detrimental for the device performances. Furthermore, GBs easily form vacancies with deep defect electronic states and are also preferential segregation sites for various impurity species as C, N and O. We studied from first-principles the correlation between structural, energetics and electronic properties of the Σ3{111} Si GB, with and without vacancies, and the segregation of C, N and O atoms. C and O atoms strongly increase their ability to segregate when vacancies are present. However, the electronic properties of the Σ3{111} Si GB are not affected by the presence of O while they can strongly change in the case of C. For N atoms it is not possible to find a clear trend in the energetics and electronic properties both with and without vacancies in the GB. In fact, as N is not isovalent with Si, as C and O, it is more flexible in finding new chemical arrangements in the GB structure. This implies a stronger difficulty in controlling the properties of the material in the presence of N impurity atoms compared to C and O impurities.

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Section: Grain Boundary Structuresmentioning

confidence: 80%

Section: B Carbon Oxygen and Nitrogen Atoms In σ3{111} Si Gb With Vac...mentioning

confidence: 96%

Section: Grain Boundary Structuresmentioning

confidence: 99%

Section: Grain Boundary Structuresmentioning

confidence: 99%

Section: Grain Boundary Structuresmentioning

confidence: 99%

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The role of Si vacancies in the segregation of O, C, and N at silicon grain boundaries: An ab initio study

Maji,

Contreras-García,

Capron

et al. 2022

Preprint

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Multicrystalline Informatics Applied to Multicrystalline Silicon for Unraveling the Microscopic Root Cause of Dislocation Generation

Yamakoshi,

Ohno,

Kutsukake

et al. 2023

Advanced Materials

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A comprehensive analysis of optical and photoluminescence images obtained from practical multicrystalline silicon wafers is conducted, utilizing various machine learning models for dislocation cluster region extraction, grain segmentation, and crystal orientation prediction. As a result, a realistic 3D model that includes the generation point of dislocation clusters is built. Finite element stress analysis on the 3D model coupled with crystal growth simulation reveals inhomogeneous and complex stress distribution and that dislocation clusters are frequently formed along the slip plane with the highest shear stress among twelve equivalents, concentrated along bending grain boundaries (GBs). Multiscale analysis of the extracted GBs near the generation point of dislocation clusters combined with ab initio calculations has shown that the dislocation generation due to the concentration of shear stress is caused by the nanofacet formation associated with GB bending. This mechanism cannot be captured by the Haasen‐Alexander‐Sumino model. Thus, this research method reveals the existence of a dislocation generation mechanism unique to the multicrystalline structure. Multicrystalline informatics linking experimental, theoretical, computational, and data science on multicrystalline materials at multiple scales is expected to contribute to the advancement of materials science by unraveling complex phenomena in various multicrystalline materials.

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First Principles Study of Aluminum Doped Polycrystalline Silicon as a Potential Anode Candidate in Li‐ion Batteries

Bhimineni,

Ko,

Cornwell

et al. 2024

Advanced Energy Materials

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Addressing sustainable energy storage remains crucial for transitioning to renewable sources. While Li‐ion batteries have made significant contributions, enhancing their capacity through alternative materials remains a key challenge. Micro‐sized silicon is a promising anode material due to its tenfold higher theoretical capacity compared to conventional graphite. However, its substantial volumetric expansion during cycling impedes practical application due to mechanical failure and rapid capacity fading. A novel approach is proposed to mitigate this issue by incorporating trace amounts of aluminum into the micro‐sized silicon electrode using ball milling. Density functional theory (DFT) is employed to establish a theoretical framework elucidating how grain boundary sliding, a key mechanism involved in preventing mechanical failure is facilitated by the presence of trace aluminum at grain boundaries. This, in turn, reduces stress accumulation within the material, reducing the likelihood of failure. To validate the theoretical predictions, capacity retention experiments are conducted on undoped and Al‐doped micro‐sized silicon samples. The results demonstrate significantly reduced capacity fading in the doped sample, corroborating the theoretical framework and showcasing the potential of aluminum doping for improved Li‐ion battery performance.

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Ab initio study of oxygen segregation in silicon grain boundaries: The role of strain and vacancies

Cited by 17 publications

References 53 publications

The role of Si vacancies in the segregation of O, C, and N at silicon grain boundaries: An ab initio study

The role of Si vacancies in the segregation of O, C, and N at silicon grain boundaries: An ab initio study

Multicrystalline Informatics Applied to Multicrystalline Silicon for Unraveling the Microscopic Root Cause of Dislocation Generation

First Principles Study of Aluminum Doped Polycrystalline Silicon as a Potential Anode Candidate in Li‐ion Batteries

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