Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Bauer, Jan; Hähnel, Angelika; Werner, P.; Zakharov, N.; Blumtritt, H.; Zuschlag, Annika; Breitenstein, O.

doi:10.1109/jphotov.2015.2494680

Cited by 29 publications

(21 citation statements)

References 62 publications

(79 reference statements)

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“…The potential dissociation of these dislocations was not investigated here as HRTEM would be necessary under various angles. However, dislocations d2 have a line that pertain to the SGB plane, {1-10} in our case, and d1 pertains to b d1 x [001] = [1][2][3][4][5][6][7][8][9][10] x [001] = [-1-10], which make them very similar to the Lomer perfect dislocations observed by Bauer et al in multicrystalline solar cells [22]. However, these types of dislocation can also be Lomer-Cotrell locks generated by two intersecting glide planes, in our case {-1-11} and {111} planes.…”

Section: Grain Boundary Structure and Misorientationssupporting

confidence: 63%

“…Lomer dislocations have also been identified at small-angle grain boundaries in mc-Si [21]. From reference [22], it can also be deduced that dislocations substructures might strongly depend on each grain orientation. The electrical activity correlates with the amount of misorientation of a given SGB, which reflects the fact that larger angles correspond to denser dislocations.…”

Section: Introductionmentioning

confidence: 96%

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Subgrains, micro-twins and dislocations characterization in monolike Si using TEM and in-situ TEM

Lantreibecq

Monchoux

Pihan

et al. 2018

Materials Today: Proceedings

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A critical aspect in the development of mono-like Silicon for photovoltaic (PV) application lies in the control of its defect microstructure. While micro-twins do not seem to represent a major concern regarding electrical activity, some dislocations and low angle grain boundaries need to be avoided in the growing process because of their recombination properties. Here, we have studied how these defects grow and interact together in order to understand what are the mechanisms responsible for their presence in the cast ingots. We show that, in our specific convex liquid-solid interface growth mode, micro-twins probably originate from this interface while dislocations and subgrains build up both by epitaxy at the solid liquid interface and through dislocation-boundary interactions in the solidified region. Post-growth TEM characterization allowed identifying constitutive dislocations of some subgrain boundaries for the case of [001] seeds. In-situ TEM straining of Si at high temperature also allowed measuring dislocation mobility at several temperatures. Those are compared to the dislocation velocities in pure Czochralski Si found in literature.

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Section: Grain Boundary Structure and Misorientationssupporting

confidence: 63%

Section: Introductionmentioning

confidence: 96%

Subgrains, micro-twins and dislocations characterization in monolike Si using TEM and in-situ TEM

Lantreibecq

Monchoux

Pihan

et al. 2018

Materials Today: Proceedings

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“…This and the presence of Ni distinguishes this defect from un‐decorated stacking faults, which otherwise show a similar appearance in LAADF STEM, see e.g., ref. .…”

Section: Performance Parameters Of the Investigated Cellsmentioning

confidence: 99%

Nickel Precipitation in Light and Elevated Temperature Degraded Multicrystalline Silicon Solar Cells

2018

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Multicrystalline silicon passivated emitter and rear contact (PERC) solar cells often show light and elevated temperature-induced degradation (LeTID) followed by a regeneration process. In previous works, it has been found that this degradation/regeneration process can be described by a model including diffusion of still unknown recombination-active point defects to the cell surface. The diffusion coefficient of this unknown species is compatible with interstitial Ni diffusion in Si. In this work, scanning transmission electron microscopy (STEM) and highly sensitive energy dispersive X-ray analysis (EDX) results from altogether 14 positions taken from two cells fabricated from neighboring wafers are evaluated, one of the cells remaining virgin and the other one LeTID degraded. In two of the degraded samples thin Nicontaining platelets are found, which are most probably nickel silicide platelets. This result is an indication that Ni can be involved in the LeTID degradation and regeneration process.

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“…However, besides showing a higher dislocation density, these regions also contain significantly smaller grains and sub‐grains, which are easily visible in electroluminescence (EL) and light beam‐induced current (LBIC) imaging . Hence, the recombination activity in these regions is, at least partly if not predominantly, due to grain boundaries and not to isolated lying (countable) dislocations, whereby small angle grain boundaries (being dense rows of dislocations) show the highest recombination activity . Therefore, in the following we will speak about “defect regions” instead of “dislocation clusters” in mc material.…”

Section: Introductionmentioning

confidence: 99%

“…[2] Hence, the recombination activity in these regions is, at least partly if not predominantly, due to grain boundaries and not to isolated lying (countable) dislocations, whereby small angle grain boundaries (being dense rows of dislocations) show the highest recombination activity. [5,6] Therefore, in the following we will speak about "defect regions" instead of "dislocation clusters" in mc material. In these defect regions, the bulk lifetime may be locally reduced by a factor of 10 or more.…”

Section: Introductionmentioning

confidence: 99%

Advanced Local Characterization of Silicon Solar Cells

Breitenstein

Frühauf

Bauer

2017

Physica Status Solidi (a)

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Solar cells made from multicrystalline silicon material, which still represent the majority of solar cells produced today, are by nature inhomogeneous devices. Their bulk excess carrier lifetime, which decisively influences the short circuit current density, the saturation current density, and the effective bulk diffusion length, may vary from position to position by an order of magnitude or more. Moreover, such cells may contain ohmic shunts and, in particular in the edge regions, positions of significant depletion region recombination current. The classical local characterization method for solar cells is light beam‐induced current (LBIC) mapping. This method does not give direct information on factors influencing the dark current density. A reliable quantitative local characterization of inhomogeneous cells can be performed by combining dark lock‐in thermography (DLIT) with electro‐ and photoluminescence (EL and PL) imaging. In this contribution, the well‐established and the most recent findings on the application of these methods are reviewed and typical application examples are presented. It is shown that luminescence imaging is most appropriate for local series resistance imaging and for qualitatively imaging of all kinds of recombination‐active defects. DLIT, on the other hand, shows a lower spatial resolution, but is most appropriate for imaging local two‐diode parameters like depletion region‐ and bulk saturation current densities, the latter allowing to draw conclusions also to the local short circuit current density. A comprehensive local characterization of silicon solar cells is possible by applying both DLIT and luminescence imaging, which complement each other.

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Recombination at Lomer Dislocations in Multicrystalline Silicon for Solar Cells

Cited by 29 publications

References 62 publications

Subgrains, micro-twins and dislocations characterization in monolike Si using TEM and in-situ TEM

Subgrains, micro-twins and dislocations characterization in monolike Si using TEM and in-situ TEM

Nickel Precipitation in Light and Elevated Temperature Degraded Multicrystalline Silicon Solar Cells

Advanced Local Characterization of Silicon Solar Cells

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