Scalable Techniques for Producing Field-Effect Passivation in High-Efficiency Silicon Solar Cells

Collett, Katherine A.; Du, Siyao; Bourret‐Sicotte, Gabrielle; Luo, Zhaohua; Hamer, Phillip; Hallam, Brett; Wilshaw, Peter R.

doi:10.1109/jphotov.2018.2872032

Cited by 9 publications

(13 citation statements)

References 48 publications

(45 reference statements)

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“…In this work it has been assumed that the charge is fully concentrated at the Si-SiO 2 interface, such that, x c = d, following findings in refs. [7,20].…”

Section: Methodsmentioning

confidence: 99%

“…Later work evaluated the transport time of K + ions in the presence of a surface electric field generated by a corona discharge. [ 7 ] It was found that at 450 °C, K + ions arrived at the Si‐SiO 2 interface within just a few seconds. In this work, we exploit such methods for deposition and delivery of ions to demonstrate that K + , Rb + , and Cs + ions can be embedded into SiO 2 , create a permanent electric field, and provide field effect surface passivation.…”

Section: Introductionmentioning

confidence: 99%

“…Surface passivation studies of SiO 2 dielectrics embedded with K + ions on 1 Ω cm n-type silicon, without a surface doping or surface field, have demonstrated that effective recombination velocities S eff < 3.3 cm s −1 can be achieved, compared with S eff ≈ 100 cm s −1 for a SiO 2 film alone. [7] While this level of passivation is substantially improved, there is further potential for improvement as surface passivation schemes performing at around S eff ≈ 1 cm s −1 have been recently reported. [15][16][17][18][19] Additionally, for high-performance passivation to be practical in commercial manufacturing it must be durable for ≈30 years under operational conditions.…”

Section: Introductionmentioning

confidence: 99%

“…Later work evaluated the transport time of K + ions in the presence of a surface electric field generated by a corona discharge. [7] It was found…”

mentioning

confidence: 99%

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Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Al‐Dhahir

Niu

et al. 2023

Adv Materials Inter

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limitation in achieving high efficiency is the recombination of electrons and holes at the silicon surface. For high efficiency PERC and TOPCon structures to exploit their full performance, superb passivation techniques are required at surfaces and interfaces in the cell. [1] A common method to reduce surface recombination is to deposit a dielectric thin film, typically a double layer of SiO 2 /SiN x , upon the silicon surface. This serves to chemically passivate the surface, while the dielectric's intrinsic charge provides an electric field that modulates charge carrier population and further reduces recombination. [2] The latter effect is commonly termed field effect or charge assisted passivation and can be exploited in a variety of solar cell technologies. [3,4] The effectiveness of such dielectrics can be further improved by extrinsic methods that modify the film properties after deposition. This work explores how field effect surface passivation in thin film dielectrics can be enhanced by adding extrinsic ionic charge. We term this kind of charged thin film an "ion-charged dielectric."In ion-charged dielectrics (ICDs), cations or anions are purposely embedded inside of the dielectric with the purpose of producing a large and permanent electric field. Such charge can add functionality and improve the performance of electronic devices, especially the surface passivation of silicon solar cells. [5] To date, the electric field in ICDs has been primarily demonstrated using embedded potassium and sodium cations, [6][7][8][9] with some work also using cesium ions. [10,11] While the field effect provided by such ions has shown promising results, it is possible that alternative positive and negative ions can provide greater control and stability. Methods of incorporating ions into dielectrics include ion implantation, [12] in situ delivery during oxidation, [6,8] or wet delivery prior to chemical vapor deposition. [10,11] Recently, a novel method of introducing ions to dielectrics extrinsically, after deposition, was proposed by the authors. [13,14] In this method an aqueous precursor containing KCl is thermally evaporated onto the SiO 2 surface followed by elevated temperature annealing to drive the ions to the Si-SiO 2 interface. Relying on pure diffusion kinetics, it was found that the transport time of K + ions across SiO 2 varied from several minutes at 500 °C to over an hour at 400 °C. Later work evaluated the transport time of K + ions in the presence of a surface electric field generated by a corona discharge. [7] It was foundThe power conversion efficiency of solar cells is strongly impacted by an unwanted loss of charge carriers occurring at semiconductor surfaces and interfaces. Here the use of ion-charged oxide nanolayers to enhance the passivation of silicon surfaces via the field effect mechanism is reported. The first report of enhanced passivation from rubidium and cesium ion-charged oxide nanolayers is provided. The charge state and formation energy of ioncharged silicon dioxide are calculated from ...

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“…In this work it has been assumed that the charge is fully concentrated at the Si-SiO 2 interface, such that, x c = d, following findings in refs. [7,20].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Later work evaluated the transport time of K + ions in the presence of a surface electric field generated by a corona discharge. [7] It was found…”

mentioning

confidence: 99%

See 2 more Smart Citations

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Al‐Dhahir

Niu

et al. 2023

Adv Materials Inter

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“…Recent work at Oxford University has demonstrated an enhanced alneal process through the migration of potassium ions to the SiO 2 /Si interface, with impressive surface recombination velocities <1 cm/s. 46,47 World record silicon solar cells with 26.7% efficiency 48 again use hydrogen to improve surface passivation. This is achieved through the use of hydrogenated amorphous silicon (a-Si:H) deposited by PECVD.…”

Section: Introduction-hydrogen Passivation In Silicon Solar Cellsmentioning

confidence: 99%

Development of advanced hydrogenation processes for silicon solar cells via an improved understanding of the behaviour of hydrogen in silicon

Hallam

Hamer

Wenham

et al. 2020

Progress in Photovoltaics

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The understanding and development of advanced hydrogenation processes for silicon solar cells are presented. Hydrogen passivation is incorporated into virtually all silicon solar cells, yet the properties of hydrogen in silicon are still poorly understood. This is largely due to the complex behaviour of hydrogen in silicon and its ability to exist in many different forms in the lattice. For commercial solar cells, hydrogen is introduced into the device through the deposition of hydrogen-containing dielectric layers and the subsequent metallisation firing process. This process can readily passivate structural defects such as grain boundaries but is ineffective at passivating numerous defects in silicon solar cells such as the boron-oxygen complex, responsible for light-induced degradation in p-type Czochralski silicon. This difficulty is due to the need to first form the boron-oxygen defect and also due to atomic hydrogen naturally occupying low-mobility and low-reactivity charge states. However, these challenges can be overcome using advanced hydrogenation processes incorporating excess carrier generation from illumination or current injection that increase the concentration of the highly mobile and reactive neutral charge state. As a result, after fast firing, additional low-temperature advanced hydrogenation processes incorporating illumination can be implemented to enable the passivation of difficult defects like the boron-oxygen complex. With the implementation of such processes for industrial silicon solar cells, efficiency improvements of 1.1% absolute can be obtained.

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Numerical modelling and simulation of a 1-D Silicon solar cell

Nayak

Mishra

Pattanaik

2021

Materials Today: Proceedings

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Scalable Techniques for Producing Field-Effect Passivation in High-Efficiency Silicon Solar Cells

Cited by 9 publications

References 48 publications

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Ion‐Charged Dielectric Nanolayers for Enhanced Surface Passivation in High Efficiency Photovoltaic Devices

Development of advanced hydrogenation processes for silicon solar cells via an improved understanding of the behaviour of hydrogen in silicon

Numerical modelling and simulation of a 1-D Silicon solar cell

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