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Averton, France

Landis S.,CEA Grenoble | Pirot M.,French National Solar Energy Institute | Monna R.,French National Solar Energy Institute | Lee Y.,CEA Grenoble | And 4 more authors.
Microelectronic Engineering | Year: 2013

A large scale patterning processes to produce patterned silicon surfaces with low reflectivity were developed for silicon solar cells. Optical design, sample manufacturing, optical characterizations and cell efficiency measurements were conducted. Optical simulations were carried out to compute the reflectivity of the patterned surface to target the optimum shape to be manufactured in the silicon substrate. Patterned surfaces were manufactured using thermal Nano Imprint Lithography over 125 125 mm2 Si-c and Simc wafer and proportional dry etching. A high aspect ratio inverted pyramid shapes were achieved in both Si-c &Si-mc substrates. An effective reflectivity (Rw) of about 3% was achieved on multi-crystalline silicon with the inverted pyramid pattern. The patterning process uniformity over the substrate was better than 97%. I(V) measurements of standard Si-mc KOH textured and Si-mc inverted pyramidal textured using Nano imprint and dry etching revealed that a drop of about 3% were induced in the open-circuit voltage, a drop of about 3.4% for the fill factor, however with an increase of about 8.3% for the short-circuit current. A gain of 0.33% absolute efficiency is obtained on the Si-mc Nano-imprinted cell compared to the KOH textured Si-mc cell. The gain of the short-circuit current is directly connected to the gain of reflectivity (8%) obtained on the finished solar cell. © 2013 Elsevier B.V. All rights reserved.

Bounaas L.,French National Solar Energy Institute | Auriac N.,French National Solar Energy Institute | Grange B.,French National Solar Energy Institute | Monna R.,French National Solar Energy Institute | And 6 more authors.
Energy Procedia | Year: 2013

Dielectric back passivated solar cells with local Al-BSF (Back Surface Field) are investigated to lead the way on achieving higher efficiencies. However the formation of efficient and uniform local BSF needs a proper opening of the dielectric passivation layers. In this paper the laser ablation mechanisms with green and ultraviolet laser sources are studied to locally remove dielectric stacks such as SiO2/SiNx. Green laser process parameters are found to lower silicon surface damages but highlight the importance of using a post-laser cleaning step based on an alkaline etching solution. The impact of this additional step on BSF formation is studied by extracting the local internal quantum efficiency from LBIC mappings of a fabricated PERC solar cell. © 2013 The Authors.

Thibert S.,MPO Energy | Thibert S.,University Grenoble alpes | Thibert S.,French National Center for Scientific Research | Jourdan J.,MPO Energy | And 4 more authors.
IEEE Journal of Photovoltaics | Year: 2015

A cooptimization procedure has been developed for industrial solar cells metalized using a nickel seed layer thickened by a plated silver layer. A theoretical contact resistivity model for NiSi nickel silicide contacts was first computed and inserted into classical power loss equations. Optical, resistive, and recombination losses were then simulated with a standard set of parameters used in production. This procedure allows the generation of efficiency and silver consumption contour plots for homogeneous and selective emitters. For both, general guidelines are given for the optimization of the doping profile, the finger spacing, and the finger thickness. © 2011-2012 IEEE.

Thibert S.,MPO Energy | Thibert S.,Grenoble Institute of Technology | Jourdan J.,MPO Energy | Bechevet B.,MPO Energy | And 3 more authors.
Conference Record of the IEEE Photovoltaic Specialists Conference | Year: 2013

With the recent introduction of ion implantation in the photovoltaic industry, it is now easier to carefully tailor the emitter doping profile. However the metallization layout should be optimized in the same time, as they are closely linked via the metal/silicon contact resistivity. In this work, an advanced co-optimization procedure allows finding out the influence of the Schottky barrier height on the metal grid design and the optimal doping profile. The theoretical electrical properties of a 2 × 2 cm2 ideal silicon solar cell are also computed for each optimal combination. According to this work, the maximal achievable efficiency decreases from 26.2 % to 25.3 % if the Schottky barrier height increases from 0.5 eV to 0.9 e V. © 2013 IEEE.

Thibert S.,MPO Energy | Thibert S.,Grenoble Institute of Technology | Jourdan J.,MPO Energy | Bechevet B.,MPO Energy | And 3 more authors.
Energy Procedia | Year: 2013

A unified model for the nickel-silicon theoretical contact resistivity was computed, using a 0.6 eV Schottky barrier height, and compared to recent experimental data. This model was subsequently inserted in a classical co-optimization procedure. Numerical simulations were combined with analytical power losses equations to find out the effect of homogeneous emitter doping profile on an ideal lab-scale silicon solar cell. According to this work, an optimized emitter for plated contacts on a 10 μm wide nickel seed layer should have a junction depth ranging from 0.5 to 4 μm and a surface doping from 4 × 1018 to 2 × 1019 cm-3. This broad range allows getting more than 25.5% and up to 25.9% theoretical efficiency on a 2 × 2 cm2 silicon solar cell metallized with 10 μm thick fingers. Finally, contour plots were also simulated using a larger Schottky barrier height in order to figure out the effect of the nickel silicide contact interface on solar cell properties. © 2013 The Authors.

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