Influence of the dopant on the contact formation to p+-type silicon

Riegel, Stefanie; Mutter, Florian; Hahn, Giso; Terheiden, Barbara

doi:10.1016/j.egypro.2011.06.178

Cited by 11 publications

(11 citation statements)

References 2 publications

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“…2(a) identifies an area where Si and bulk Ag conductor line (sintered Ag particles) appears to be "touching." These ultrathin interfacial glass with nano-Ag colloids regions of FS contact of p-type Si cells were in detail investigated and previously reported [8]- [10], [12]- [14]. The microstructures revealed by our SEM images of these n-type Si cell contacts are consistent with our previously proposed conduction model using nano-Ag colloids-assisted tunneling [14]- [16].…”

Section: Resultssupporting

confidence: 88%

Current Conduction Mechanism of Front-Side Contact of N-Type Crystalline Si Solar Cells With Ag/Al Pastes

Liang

Cheng

et al. 2014

IEEE J. Photovoltaics

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Recently, n-type crystalline Si (c-Si) cells with frontside (FS) metallization Ag/Al paste have attracted considerable attention. However, a clear understanding of current conduction mechanism is still lacking. We report here the results of our microstructural investigation of the interfacial contact region using electron microscopy techniques. In optimally fired cells, we did not find any Al-Si eutectic layer on the emitter surface that would support a regrowth mechanism as found during the back surface field formation process commonly practiced to create the full plane Al back contact of p-type industrial solar cells. The presence of SiN x antireflection coating has possibly altered significantly the chemistry between Si and Al. The observed microstructures suggest that the current conduction is predominantly tunneling through ultrathin interfacial glass, assisted by the presence of nano-Ag colloids. We believe this mechanism is similar to the current conduction model we have proposed previously for FS Ag-contact of p-type c-Si solar cells with Ag paste.

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Section: Resultssupporting

confidence: 88%

Current Conduction Mechanism of Front-Side Contact of N-Type Crystalline Si Solar Cells With Ag/Al Pastes

Liang

Cheng

et al. 2014

IEEE J. Photovoltaics

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“…For the realization of highly efficient n‐type silicon solar cells, the front boron emitter presents several challenges. First, metallization for achieving low contact resistivity for the boron emitter is difficult because the conventional Ag paste cannot be used, and Ag‐Al paste induces high recombination current density for the boron emitter contact . Fraunhofer ISE also used the Ti/Pd/Ag evaporation method employing photolithography for the front contact .…”

Section: Introductionmentioning

confidence: 99%

Tunnel oxide passivating electron contacts for high‐efficiency n‐type silicon solar cells with amorphous silicon passivating hole contacts

Park

Lee

Park

et al. 2019

Progress in Photovoltaics

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This study proposes a hybrid solar cell structure for a highly efficient silicon solar cell obtained by combining two passivating contact structures, namely, a heterojunction and polysilicon passivating contact. Given that the major cause of the loss in efficiency of crystalline silicon solar cells is carrier recombination at the metal‐semiconductor junction, a passivating contact having high‐quality passivation and a low contact resistance was introduced. In this study, two major passivating contact solar cells were combined. By applying an intrinsic thin amorphous silicon layer at the front and a tunneling oxide at the rear, a hybrid silicon solar cell with an efficiency of 21.8% was fabricated. Moreover, to evaluate the potential efficiency limit and to suggest methods for improving the cell performance of the proposed amorphous silicon emitter tunnel oxide back contact structure, the cell efficiency was simulated, and the result indicated that an efficiency of 26% could be achieved by controlling the thickness and resistivity of the wafer.

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“…[11][12][13][14] In this paper, we report in detail the microstructure of Ag/Al FS contact of n-type c-Si solar cells with SiN x ARC. The firing temperature(s) required for optimal cell performance was carefully identified.…”

Section: Discussionmentioning

confidence: 99%

“…Several papers have been published concerning the current conduction mechanism of these Ag/Al pastes. Lago 11 and Riegel [12][13][14] reported their microstructural investigation of FS contacts printed with Ag/Al pastes on "model" n-type c-Si cells without SiN x anti-reflective coating (ARC). However, it remained unclear whether their findings are applicable to an actual industrial cell where a SiNx ARC is always present.…”

mentioning

confidence: 99%

Microstructural characterization and current conduction mechanisms of front-side contact of n-type crystalline Si solar cells with Ag/Al pastes

Liang

Cheng

et al. 2015

Journal of Applied Physics

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Recently, high efficiency n-type crystalline Si cells made with the screen printed Ag/Al metallization have received considerable attention. We report here our microstructural investigations of the critical interfacial region between the front-side contact and the Si wafer of n-type cells fired under progressively higher temperatures. Our study revealed that the key characteristic microstructures of the interfacial region changed from one with a large fraction of residual SiNx, to one consisting of a thin glass layer with nano-Ag colloids, and finally to one decorated with Ag and Ag/Al crystallites attached to the emitter surface for cells with under-, optimally-, and over-fired conditions, respectively. We did not find any Al-Si eutectic layer on the emitter surface that would support a silicon dissolution and re-growth mechanism, which is operative in the back surface field formation process for the Al back contact of p-type industrial solar cells. The presence of the SiNx antireflection coating has likely altered the chemistry between Si and Al significantly. The observed microstructures lead us to conclude that the main current conduction mechanism in optimally-fired n-type cells is tunneling through those areas of thin interfacial glass containing nano-Ag colloids. This mechanism is similar to the current conduction model we have proposed previously for optimally-fired p-type crystalline Si solar cells. We believe that the intrusion of Ag/Al (and/or Ag) crystallites into the p+-Si emitter in over-fired cells is one of the major sources of metallization-induced recombination losses, which degrades cell performance.

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Influence of the dopant on the contact formation to p+-type silicon

Cited by 11 publications

References 2 publications

Current Conduction Mechanism of Front-Side Contact of N-Type Crystalline Si Solar Cells With Ag/Al Pastes

Current Conduction Mechanism of Front-Side Contact of N-Type Crystalline Si Solar Cells With Ag/Al Pastes

Tunnel oxide passivating electron contacts for high‐efficiency n‐type silicon solar cells with amorphous silicon passivating hole contacts

Microstructural characterization and current conduction mechanisms of front-side contact of n-type crystalline Si solar cells with Ag/Al pastes

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