Boron doping of silicon using coalloying with aluminium

Lölgen, P.; Sinke, W.C.; Leguijt, C.; Weeber, A.W.; Alkemade, P.F.A.; Verhoef, L.A.

doi:10.1063/1.112992

Cited by 36 publications

(12 citation statements)

References 2 publications

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“…In a conventional solar cell, a thick Al film is deposited onto a wafer backside and then annealed to avoid the parasitic p-n junction. Nevertheless, the surface recombination velocity at the Al-Si alloy rear contact is relatively high because a doping concentration is not more than 3 × 10 18 cm -3 [9]. In our results, however, the surface concentration of boron SOD diffusion lies in the range of 7 to 8 x 10 20 cm -3 .…”

Section: Resultscontrasting

confidence: 67%

A novel photovoltaic nanodevice based on the co-integration of silicon micro and nanowires prepared by electroless etching with conformal plasma doping

Jung

et al. 2009

2009 IEEE International Electron Devices Meeting (IEDM)

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Periodically patterned co-integration of silicon microwires (MWs) and nanowires (NWs) were applied for a novel photovoltaic (PV) nanodevice. The optical improvement due to antireflection enhancement with a graded-refractive-index (GRI) effect (see Fig. 1) was observed by employing the tapered NWs. Si MWs that formed a radial p-n junction were located in between the dense array of Si NWs. These wire arrays were cost-effectively defined by metal-assisted electroless wet etching. The co-integrated nanostructure of Si NWs and MWs demonstrated a high short circuit current (J sc ) and cell conversion efficiency (CE) compared to a sole array of Si NWs or MWs. Highest values of J sc and CE at 1.5AM illumination were recorded as 24.89 mA/cm 2 and 8.45%, respectively, which have been champion data reported to date in wire based PV cells using a radial p-n junction.

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Section: Resultscontrasting

confidence: 67%

A novel photovoltaic nanodevice based on the co-integration of silicon micro and nanowires prepared by electroless etching with conformal plasma doping

Jung

et al. 2009

2009 IEEE International Electron Devices Meeting (IEDM)

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“…The resulting profiles for paste D are shown in Figure . Please note that actual BSF profiles show higher electrically active dopant concentrations in measured electrochemical capacitance voltage profiles, because modern pastes contain additional p‐type dopants such as boron . It is also conceivable that they could contain alloying agents that alter the maximum solid‐state solubility of Al in epitaxially grown Si in a ternary material system .…”

Section: Calculation Of Resulting Doping Profilementioning

confidence: 99%

“…Model of local Al-BSF formation for industrial PERC solar cells T. Lauermann et al pastes contain additional p-type dopants such as boron [23,24]. It is also conceivable that they could contain alloying agents that alter the maximum solid-state solubility of Al in epitaxially grown Si in a ternary material system [25].…”

Section: Calculation Of Resulting Doping Profilementioning

confidence: 99%

Diffusion-based model of local Al back surface field formation for industrial passivated emitter and rear cell solar cells

Lauermann

Fröhlich

Hahn

et al. 2013

Prog. Photovolt: Res. Appl.

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In this work, the back surface field (BSF) formation of locally alloyed Al‐paste contacts employed in recent industrial passivated emitter and rear cell solar cell designs is discussed. A predictive model for resulting local BSF thickness and doping profile is proposed that is based on the time‐dependent Si distribution in the molten Al paste during the firing step. Diffusion of Si in liquid Al away from the contact points is identified as the main differentiator to a full‐area Al‐BSF; therefore, a diffusion‐based solution to the involved differential equation is pursued. Data on the Si distribution in the Al and the resulting BSF structures are experimentally obtained by firing samples with different metal contact geometries, peak temperature times and pastes as well as by investigating them by means of scanning electron microscopy and energy dispersive X‐ray spectroscopy. The Si diffusivity in the Al paste is then calculated from these results. It is found that the diffusivity is strongly dependent on the paste composition. Furthermore, the local BSF doping profiles and thicknesses resulting from different contact geometries and paste parameters are calculated from the Si concentration at the contact sites, the diffusivity and solubility data. These profiles are then used in a finite element device simulator to evaluate their performance on solar cell level. With this approach, a beneficial paste composition for any given rear contact geometry can be determined. Two line widths are investigated, and the effects of the different paste properties are discussed in the light of the solar cell results obtained by simulation. Copyright © 2013 John Wiley & Sons, Ltd.

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“…For example, rear side recombination in the Al-Si contact is high since the concentration of Al in the Al-Si alloy is less than 3 Â 10 18 cm À3 . 2 A high (600 cm s À1 ) back surface recombination velocity (BSRV) and poor back surface reectance of 60% results 1 when Al-BSF is used, which are not suitable properties for high efficiency solar cells. These electrical and optical properties deteriorate further when Si wafer thickness is reduced.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of c-Si solar cells using boric acid as a spin-on dopant for back surface field

2014

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Cost effective solar cells are paramount for solar power to compete with traditional power generation. Here we present results on two low cost, both side textured c-Si solar cells. One solar cell had an Al back surface field (BSF), while the other had boron BSF fabricated by using spin-on boric acid as a p-type dopant. As compared to the Al-BSF solar cell, an improvement in efficiency of 1.7% was observed for a solar cell with boron BSF. Since boron BSF is stronger than Al-BSF, an improvement in efficiency can be attributed to an increase in long wavelength response, collection efficiency and reduced back surface recombination. The boron BSF solar cell showed an efficiency of 12.9% with V oc of 0.56 V, J sc of 32.2 mA cm À2 and FF of 0.72. These parameters are expected to significantly increase further with the addition of layers such as anti-reflection/passivation layers at the front side, and back surface passivation with local back surface field, etc.

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Boron doping of silicon using coalloying with aluminium

Cited by 36 publications

References 2 publications

A novel photovoltaic nanodevice based on the co-integration of silicon micro and nanowires prepared by electroless etching with conformal plasma doping

A novel photovoltaic nanodevice based on the co-integration of silicon micro and nanowires prepared by electroless etching with conformal plasma doping

Diffusion-based model of local Al back surface field formation for industrial passivated emitter and rear cell solar cells

Fabrication of c-Si solar cells using boric acid as a spin-on dopant for back surface field

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