Stable, Extrinsic, Field Effect Passivation for Back Contact Silicon Solar Cells

Collett, Katherine A.; Rands, Lucy; Martins, George; Lobo, Richard; Wilshaw, Peter R.

doi:10.4028/www.scientific.net/ssp.242.67

Cited by 15 publications

(14 citation statements)

References 13 publications

(20 reference statements)

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“…Additional work by the same authors has provided evidence of stable and controlled FEP. 61 Figure 7 also shows the difference in passivation provided by positive versus negative charges. This asymmetry is a characteristic feature of the interfacial physical properties and had been first pointed out by Girisch 15 when setting the surface SRH model.…”

Section: Discussionmentioning

confidence: 99%

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On the c-Si/SiO2 interface recombination parameters from photo-conductance decay measurements

Wilshaw

2017

Journal of Applied Physics

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The recombination of electric charge carriers at semiconductor surfaces continues to be a limiting factor in achieving high performance optoelectronic devices, including solar cells, laser diodes, and photodetectors. The theoretical model and a solution algorithm for surface recombination have been previously reported. However, their successful application to experimental data for a wide range of both minority excess carrier concentrations and dielectric fixed charge densities has not previously been shown. Here, a parametrisation for the semiconductor-dielectric interface charge Qit is used in a Shockley-Read-Hall extended formalism to describe recombination at the c-Si/SiO2 interface, and estimate the physical parameters relating to the interface trap density Dit, and the electron and hole capture cross-sections σn and σp. This approach gives an excellent description of the experimental data without the need to invoke a surface damage region in the c-Si/SiO2 system. Band-gap tail states have been observed to limit strongly the effectiveness of field effect passivation. This approach provides a methodology to determine interface recombination parameters in any semiconductor-insulator system using macro scale measuring techniques.

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Section: Discussionmentioning

confidence: 99%

“…61 Previous research has mainly focused on the effect of the surface charge on the effective lifetime of silicon for one excess minority carrier concentration or one surface charge density. [62][63][64] Here, the dependence of surface recombination velocity on both independent variables is explored.…”

Section: Application To Oxide Passivated N-type C-simentioning

confidence: 99%

On the c-Si/SiO2 interface recombination parameters from photo-conductance decay measurements

Wilshaw

2017

Journal of Applied Physics

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“…Despite this, some of the most electrically inactive surfaces have been obtained using such techniques. Bonilla et al have used corona discharge or alkali ionic species to extrinsically charge oxide films and improve their FEP properties. They also performed forming gas anneals to extrinsically incorporate H to the interface and combine it with extrinsic corona FEP .…”

Section: Materials and Methods For Silicon Surface Passivationmentioning

confidence: 99%

Dielectric surface passivation for silicon solar cells: A review

Bonilla

Hoex

Hamer

et al. 2017

Physica Status Solidi (a)

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This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.Silicon wafer solar cells continue to be the leading photovoltaic technology, and in many places are now providing a substantial portion of electricity generation. Further adoption of this technology will require processing that minimises losses in device performance. A fundamental mechanism for efficiency loss is the recombination of photo-generated charge carriers at the unavoidable cell surfaces. Dielectric coatings have been shown to largely prevent these losses through a combination of different passivation mechanisms. This review aims to provide an overview of the dielectric passivation coatings developed in the past two decades using a standardised methodology to characterise the metrics of surface recombination across all techniques and materials. The efficacy of a large set of materials and methods has been evaluated using such metrics and a discussion on the current state and prospects for further surface passivation improvements is provided.

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“…High frequency capacitance-voltage (CV) was performed in an Agilent E4980AL Precision LCR Meter. Kelvin probe (KP) measurements were carried out using a modified Scanning Kelvin Probe from KP Technology as described in [28].…”

Section: Characterisationmentioning

confidence: 99%

Passivation of all-angle black surfaces for silicon solar cells

Rahman

Bonilla

Nawabjan

et al. 2017

Solar Energy Materials and Solar Cells

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Abstract-Optical losses at the front surface of a silicon solar cell have a significant impact on efficiency, and as such, efforts to reduce reflection are necessary. In this work, a method to fabricate and passivate nanowire-pyramid hybrid structures formed on a silicon surface via wet chemical processing is presented. These high surface area structures can be utilised on the front surface of back contact silicon solar cells to maximise light absorption therein. Hemispherical reflectivity under varying incident angles is measured to study the optical enhancement conferred by these structures. The significant reduction in reflectivity (<2%) under low incident angles is maintained at high angles by the hybrid textured surface compared to surfaces textured with nanowires or pyramids alone. Finite Difference Time Domain simulations of these dual micro-nanoscale surfaces under varying angles supports the experimental results. In order to translate the optical benefit of these high surface area structures into improvements in device efficiency, they must also be well passivated. To this end, atomic layer deposition of alumina is used to reduce surface recombination velocities of these ultra-black silicon surfaces to below 30 cm/s. A decomposition of the passivation components is performed using capacitance-voltage and Kelvin Probe measurements. Finally, device simulations show power conversion efficiencies exceeding 21% are possible when using these ultra-black Si surfaces for the front surface of back contact silicon solar cells.

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Stable, Extrinsic, Field Effect Passivation for Back Contact Silicon Solar Cells

Cited by 15 publications

References 13 publications

On the c-Si/SiO2 interface recombination parameters from photo-conductance decay measurements

On the c-Si/SiO2 interface recombination parameters from photo-conductance decay measurements

Dielectric surface passivation for silicon solar cells: A review

Passivation of all-angle black surfaces for silicon solar cells

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