Drift characteristics of mobile ions in SiNx films and solar cells

Wilson, Marshall; Savtchouk, Alexandre; Edelman, Piotr; Marinskiy, Dmitriy; Łagowski, J.

doi:10.1016/j.solmat.2015.06.022

Cited by 39 publications

(27 citation statements)

References 6 publications

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“…A major question is which process leads to the observed Si oxidation. According to the mechanism described for cathodic corrosion, we assume the following formation stages: 1) In the study by Wilson et al, it was demonstrated that Na can drift through SiN y layers, due to the presence of a strong electrical field. We assume that, alkali metal ions drift toward the Si/AlO x interface.…”

mentioning

confidence: 99%

Local Corrosion of Silicon as Root Cause for Potential‐Induced Degradation at the Rear Side of Bifacial PERC Solar Cells

Sporleder

Bauer

Richter

et al. 2019

Physica Rapid Research Ltrs

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Industrial bifacial PERC solar cells are exposed to a high‐voltage stress at the rear side. The tested cells show a potential‐induced degradation (PID) in Voc and Isc. From a front side current–voltage measurement, a power loss of about 12%rel is observed, however, without a significant change in the fill factor. The degradation is traced back to micron‐sized hole‐shaped damages of the rear surface, which correlate with localized regions of increased recombination. A focused ion beam (FIB) cross‐section through a hole‐shaped damage is performed for subsequent transmission electron microscopy (TEM) and energy‐dispersive X‐ray spectroscopy (EDXS). EDXS shows an accumulation of Na, K, and Ca impurities in the cavity. Thus, it is assumed that corrosion of the Si surface occurs beneath the AlOx/SiNy passivation layer stack and is accompanied by the formation of a SiO2 layer.

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mentioning

confidence: 99%

Local Corrosion of Silicon as Root Cause for Potential‐Induced Degradation at the Rear Side of Bifacial PERC Solar Cells

Sporleder

Bauer

Richter

et al. 2019

Physica Rapid Research Ltrs

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show abstract

“…This fact suggests that, with the assistance of a strong electric field, Na can pass easily even through SiN x passivation layers, which are known as diffusion barriers for Na. [ 88 ] According to findings reported by Wilson et al, [ 89 ] in an electric field of 0.5 MV cm −1 and 80 °C, the drift time for Na + across an 80 nm SiN x film is ≈25 min. These experimentally obtained results confirmed the ease of Na penetration under PID stress.…”

Section: Pid Phenomena In Conventional P‐type C‐si Pv Cell Modulesmentioning

confidence: 85%

“…In fact, Na + ions are known to be introduced into the c‐Si substrate from the cell surface through SiN x passivation layers by PID stress. [ 84,89 ]…”

Section: Na‐penetration‐type Pidmentioning

confidence: 99%

Potential‐Induced Degradation in High‐Efficiency n‐Type Crystalline‐Silicon Photovoltaic Modules: A Literature Review

et al. 2021

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n‐Type crystalline‐silicon (c‐Si) photovoltaic (PV) cell modules attract attention because of their potential for achieving high efficiencies. The market share of n‐type c‐Si PV modules is expected to increase considerably, with wide use in PV systems, including large‐scale PV systems, for which the system bias is set as markedly high. Such a high system bias leads to performance losses known as potential‐induced degradation (PID). By virtue of many researchers’ efforts, the PID behaviors, mechanisms, and preventive measures against PID have been well documented in conventional p‐type c‐Si modules. Researchers recently started to investigate PID in high‐efficiency c‐Si solar cells including n‐type c‐Si PV modules. Yet, the understanding of PID phenomena remains incomplete. Herein, a literature review of PID in high‐efficiency n‐type c‐Si PV modules is provided as a resource elucidating the current status of related research and remaining unresolved issues. This report mainly presents discussion of PID in several kinds of n‐type c‐Si PV modules in terms of materials science. PID phenomena are described as divided into some degradation modes. Details present a review of their respective degradation modes, degradation behaviors, proposed mechanisms, and potential measures against degradation. Remaining open issues and anticipated future studies are also summarized.

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“…It is also possible that positive ions, e.g., Na + , are responsible for or involved in the depolarization of the passivation layers at the rear side. Wilson et al [ 27 ] investigated the drift of Na + through PECVD SiN Y : at 50 °C and at the field strength of 1 MV cm −1 , the drift velocity of Na + in SiN Y is v (Na + ) = 0.1 nm s −1 . Thus, it would take Na + ions about 13 min, to drift through the 80 nm thick SiN Y passivation layer at the rear side of the PERC+ solar cell.…”

Section: Discussionmentioning

confidence: 99%

Time‐Resolved Investigation of Transient Field Effect Passivation States during Potential‐Induced Degradation and Recovery of Bifacial Silicon Solar Cells

et al. 2021

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Various types of potential‐induced degradation (PID) with fundamentally different physical root causes have been observed recently ranging from shunting (PID‐s), corrosion (PID‐c) to degradation of surface passivation (PID‐p). Herein, PID‐p is investigated for the first time at the rear side of bifacial silicon solar cells with enhanced time‐resolution during degradation and recovery under simultaneous illumination. The tests reveal fast transient changes of rear‐side short‐circuit current within minutes and thus allow to understand the degradation process related to PID‐p. The short‐circuit current with rear‐side illumination first decreases significantly by more than 80 % resulting in an intermediate degraded state. Subsequently, it increases to a regenerated state. Under reversed bias, a total recovery of the cell parameters is observed and confirmed by I–V measurements under standard testing conditions (STCs). The underlying transient PID‐p degradation and recovery mechanism is well described by a PC‐1D simulation of the field‐induced band bending at the rear surface. Finally, a qualitative model involving the migration of mobile charged species and their impact on the charge equilibrium in the field effect passivation layer is presented. Thus, time‐resolved analysis of transient PID effects can serve as a clear characteristic for PID of polarization type.

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Drift characteristics of mobile ions in SiNx films and solar cells

Cited by 39 publications

References 6 publications

Local Corrosion of Silicon as Root Cause for Potential‐Induced Degradation at the Rear Side of Bifacial PERC Solar Cells

Local Corrosion of Silicon as Root Cause for Potential‐Induced Degradation at the Rear Side of Bifacial PERC Solar Cells

Potential‐Induced Degradation in High‐Efficiency n‐Type Crystalline‐Silicon Photovoltaic Modules: A Literature Review

Time‐Resolved Investigation of Transient Field Effect Passivation States during Potential‐Induced Degradation and Recovery of Bifacial Silicon Solar Cells

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