Factors Limiting the Formation of Uniform and Thick Aluminum–Back-Surface Field and Its Potential

Meemongkolkiat, Vichai; Nakayashiki, Kenta; Kim, Dong Seop; Kopecek, Radovan; Rohatgi, A.

doi:10.1149/1.2129106

Cited by 69 publications

(25 citation statements)

References 13 publications

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“…Indeed, visible blistering of the Al film was observed on all cells fired at the highest temperature. This blistering has been shown to result in highly nonuniform Al-BSF formation which ultimately degrades the minority carrier potential barrier provided by the Al-BSF layer as well as V OC and J SC [20].…”

Section: A Pocl 3 Emitter Characterizationmentioning

confidence: 99%

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Cooper

Tate

Renshaw

et al. 2014

IEEE J. Photovoltaics

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Screen-printed thick-film Ag metallization has become highly successful in crystalline Si (c-Si) photovoltaics. However, a complete understanding of the mechanism resulting in low resistance contact is still lacking. In order to shed light on this mechanism for current-generation Ag paste, Si solar cells were fabricated using a range of emitter doping densities and contact firing conditions. Low resistance contact was found to vary as a function of emitter surface P concentration ([P su rface ]) and peak firing temperature. Scanning electron microscope (SEM) analysis revealed thin interfacial glass films (IGF) under the bulk Ag gridline. SEM analysis also showed increasing Ag crystallite density as both emitter [P su rface ] and peak firing temperature increased. Two mechanisms are proposed in forming low resistance contact to highly doped emitters: 1) formation of ultrathin IGF and/or nano-Ag colloids at low firing temperature, and 2) formation of Ag crystallites at high firing temperature. However, on lightly doped emitters, low resistance contact was achieved only at higher firing temperatures, concomitant with increasing Ag crystallite density, and suggests that thin IGF decorated with nano-Ag colloids may not be sufficient for low resistance contact to lightly doped emitters.

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Section: A Pocl 3 Emitter Characterizationmentioning

confidence: 99%

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Cooper

Tate

Renshaw

et al. 2014

IEEE J. Photovoltaics

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“…Therefore, the BSF layer thickness control and uniformity are majorly focused since solar cell characteristics are varied by these factors 7,8) . BSF layer thickness is normally followed by quantity of dissolved Si onto Al-Si melted layer at peak temperature 1,8) . The uniformity of BSF layer is also related to the firing peak temperature.…”

Section: )mentioning

confidence: 99%

Investigation of Firing Conditions for Optimizing Aluminum-Doped p⁺-layer of Crystalline Silicon Solar Cells

Lee¹,

Lee²,

Shin³

et al. 2016

Current Photovoltaic Research

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Screen printing technique followed by firing has commonly been used as metallization for both laboratory and industrial based solar cells. In the solar cell industry, the firing process is usually conducted in a belt furnace and needs to be optimized for fabricating high efficiency solar cells. The printed-Al layer on the silicon is rapidly heated at over 800°C which forms a layer of back surface field (BSF) between Si-Al interfaces. The BSF layer forms p-p + structure on the rear side of cells and lower rear surface recombination velocity (SRV). To have low SRV, deep p + layer and uniform junction formation are required. In this experiment, firing process was carried out by using conventional tube furnace with N2 gas atmosphere to optimize Voc of laboratory cells. To measure the thickness of BSF layer, selective etching was conducted by using a solution composed of hydrogen fluoride, nitric acid and acetic acid. The Voc and pseudo efficiency were measured by Suns-Voc to compare cell properties with varied firing condition.

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“…Doping profiles for AI-LBSF simulation. The method for extending the ECV profiles was from [12] and [13].…”

Section: B Optical Parametersmentioning

confidence: 99%

Structure simulation of screen printed local back surface field for rear passivated silicon solar cells

Chen

Liang

Yang

et al. 2012

2012 38th IEEE Photovoltaic Specialists Conference

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The research of this paper was focused on the simulation of screen printed Local Back Surface Field (LBSF) for the rear passivated solar cells. The thickness, homogeneity and cavity effect were studied. According to the simulation results, the thickness of LBSF should be at least 2 ,.. m in order to gain high efficiency of solar cells. If LBSF was thick enough, the homogeneity of LBSF had less impact on the cell performance. However, the incomplete formation of LBSF layer would drastically decrease the open circuit voltage (Voc) of cells. The thinnest part of an inhomogeneous LBSF should be 1 to 2 ,.. m at the least. As for the influence of the cavities inside the local contacts, a single long cavity would cause a power loss of 8.20%to 11.15% relatively, and the cavity group made up of many long cavities would cause a power loss of about 11.53% tol00% relatively.

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Factors Limiting the Formation of Uniform and Thick Aluminum–Back-Surface Field and Its Potential

Cited by 69 publications

References 13 publications

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Investigation of Firing Conditions for Optimizing Aluminum-Doped p⁺-layer of Crystalline Silicon Solar Cells

Structure simulation of screen printed local back surface field for rear passivated silicon solar cells

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Factors Limiting the Formation of Uniform and Thick Aluminum–Back-Surface Field and Its Potential

Cited by 69 publications

References 13 publications

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Investigation of the Mechanism Resulting in low Resistance Ag Thick-Film Contact to Si Solar Cells in the Context of Emitter Doping Density and Contact Firing for Current-Generation Ag Paste

Investigation of Firing Conditions for Optimizing Aluminum-Doped p+-layer of Crystalline Silicon Solar Cells

Structure simulation of screen printed local back surface field for rear passivated silicon solar cells

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Investigation of Firing Conditions for Optimizing Aluminum-Doped p⁺-layer of Crystalline Silicon Solar Cells