Improved amorphous silicon passivation layer for heterojunction solar cells with post-deposition plasma treatment

Neumüller, Alex; Sergeev, Oleg; Heise, Stephan J.; Bereznev, Sergei; Volobujeva, Olga; Salas, J. F. López; Vehse, Martin; Agert, Carsten

doi:10.1016/j.nanoen.2017.11.053

Cited by 19 publications

(9 citation statements)

References 35 publications

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“…These results show that H atoms have both local impact in an amorphous network and cause nonlocal changes in the physical and electronic structures. This finding suggests that annealing processes in the presence of H atoms can positively impact the quality of the a-Si:H/c-Si heterojunction if H can find its most stable configuration, consistent with recent experimental results …”

Section: Resultssupporting

confidence: 92%

“…This finding suggests that annealing processes in the presence of H atoms can positively impact the quality of the a-Si:H/c-Si heterojunction if H can find its most stable configuration, consistent with recent experimental results. 57 Figure 10 shows the plot of the calculated IPR of all Kohn− Sham orbitals obtained via DFT versus energy for a-Si:H/c-Si in its first three stable configurations. It is obvious from the figure that regardless of the H bonding configuration, H addition strongly decreases the localization of the electronic states in the a-Si/c-Si heterostructure.…”

Section: Defect States and Orbitalmentioning

confidence: 99%

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Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Meidanshahi¹,

Vasileska²,

Goodnick³

2021

J. Phys. Chem. C

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In this paper, we explore the effect of H and its bonding configurations on the defect state density and orbital localization of hydrogenated amorphous Si (a-Si:H)/crystalline Si (c-Si) heterostructures using density functional theory (DFT) studies of model interfaces between amorphous silicon (a-Si)/a-Si:H and c-Si. To model the atomic configuration of a-Si on c-Si, melting and quenching simulations were performed using classical molecular dynamics. Different hydrogen contents were inserted into a-Si in different bonding configurations followed by DFT relaxation to create stable structures of a-Si:H representative of hydrogenated a-Si on crystalline Si surfaces. In contrast to typical Si heterojunctions (e.g., Si/SiO2, where the defect density is maximum at the interface), we find that the defect state density is low at the interface and maximum in the bulk of a-Si. Structural analysis shows that in these configurations, H atoms do not necessarily bond to dangling bonds or to interface atoms. However, they are able to significantly change the atomic structure of the heterostructure and consequently decrease the density of defect states and orbital localization in the a-Si layer, particularly at the interface of a-Si/c-Si. The general form of the simulated defect state distribution demonstrates the passivating role of a-Si:H on c-Si substrates.

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Section: Resultssupporting

confidence: 92%

Section: Defect States and Orbitalmentioning

confidence: 99%

Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Meidanshahi¹,

Vasileska²,

Goodnick³

2021

J. Phys. Chem. C

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“…In this perspective article, we first reviewed the history of SHJ solar cells and BO defects. This helped us to draw a timeline [92,94,95,[97][98][99][100][101][102][103][104][105] Figure 7. Minority carrier effective lifetime as a function of injection-level for p-and n-type wafers passivated with in þ and ip þ stacks reported by Descoeudres et al in 2013 and 2020.…”

Section: Final Thoughtsmentioning

confidence: 99%

Silicon Heterojunction Solar Cells and p‐type Crystalline Silicon Wafers: A Historical Perspective

et al. 2022

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The first reports of both boron–oxygen (BO)‐related light‐induced degradation (BO‐LID) and amorphous/crystalline silicon heterojunction (SHJ) solar cell fabrication date back to the early 1970s. However, the complete development of the “modern” SHJ structure took place well before BO defect stabilization processes were developed. Due to the susceptibility of p‐type Czochralski (Cz)‐grown silicon to BO‐LID, such wafers were deemed unsuitable for SHJ solar cells. In addition to stability issues, lower charge carrier lifetimes due to contamination and challenges with surface passivation posed barriers to the adoption of p‐type wafers in SHJ applications. Herein, these three key challenges are discussed in detail. Kinetic modeling and experimental results reveal the severe impact of BO‐LID in p‐type SHJ solar cells and provide possible explanations as to why earlier attempts using p‐type wafers might have failed. The role of gettering and advanced hydrogenation in stabilizing BO defects in SHJ solar cells is demonstrated experimentally. Finally, a summary of the effective surface recombination velocities reported in the literature for hydrogenated intrinsic amorphous silicon passivation of p‐ and n‐type crystalline silicon wafers is presented. Based on these findings, the potential of p‐type wafers to enable a next‐generation of high‐efficiency solar cells featuring carrier‐selective contacts is discussed.

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“…[2] To achieve high V oc , many efforts have been endeavored, such as pretreatment of silicon wafer surface before i-a-Si:H deposition, [3][4][5][6] controlling i-a-Si:H deposition, [7][8][9] suppressing epitaxial growth, [7] plasma treatment (PT) after i-a-Si:H deposition. [10][11][12][13][14] Hydrogen plasma treatment (HPT) is an effective approach to improve a-Si:H/c-Si interface passivation. However, etching [15] and crystallization of a-Si:H [16] induced by HPT, indicate that its application in passivation should be treated with care.For SHJ, the optical losses mainly lie in doped a-Si:H and TCO due to reflection and parasitic absorption, especially at the doped layer on the illuminated side of SHJ.…”

mentioning

confidence: 99%

“…[32] However, that report lacks in the analysis of CO 2 PT, modifying i-a-Si:H and inducing nucleation of p-nc-Si:H. On the other hand, ion bombardment is not as detrimental as is often thought because it could be beneficial for SHJ solar cells within the energy range. [13,33] Therefore, optimized CO 2 PT of i-a-Si:H can be a bifunctional method to effectively arrange i-a-Si:H/c-Si interface and to form seed interface at i/p. In this work, CO 2 PT at the i/p interface, and the effect of ion bombardment on i-a-Si:H/c-Si interface and the component of i-a-Si:H surface are studied.…”

mentioning

confidence: 99%

Bifunctional CO₂ Plasma Treatment at the i/p Interface Enhancing the Performance of Planar Silicon Heterojunction Solar Cells

Yan

Huang

Ren

et al. 2021

Physica Rapid Research Ltrs

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Passivation techniques are regarded as an effective strategy to obtain high-efficiency crystalline silicon (c-Si) solar cells. These include field-effect passivation and chemical passivation. [1] Among high-performance devices, intrinsic hydrogenated amorphous silicon (i-a-Si:H) provides outstanding chemical passivation on the surface of c-Si by saturating the dangling bonds and thus reducing the density of interface. Then, with the addition of thin doped silicon films, transparent conducting oxides (TCOs), and metal contacts, silicon heterojunction (SHJ) solar cells with an open-circuit voltage (V oc ) of 750 mV have been achieved. [2] To achieve high V oc , many efforts have been endeavored, such as pretreatment of silicon wafer surface before i-a-Si:H deposition, [3][4][5][6] controlling i-a-Si:H deposition, [7][8][9] suppressing epitaxial growth, [7] plasma treatment (PT) after i-a-Si:H deposition. [10][11][12][13][14] Hydrogen plasma treatment (HPT) is an effective approach to improve a-Si:H/c-Si interface passivation. However, etching [15] and crystallization of a-Si:H [16] induced by HPT, indicate that its application in passivation should be treated with care.For SHJ, the optical losses mainly lie in doped a-Si:H and TCO due to reflection and parasitic absorption, especially at the doped layer on the illuminated side of SHJ. [17,18] Compared with doped a-Si:H or hydrogenated amorphous silicon oxide (a-SiO x :H) layers, hydrogenated nanocrystalline silicon (nc-Si:H) or hydrogenated nanocrystalline silicon oxide (nc-SiO x :H) as window layers have a better potential to improve the short-circuit current density ( J SC ) of SHJ solar cells due to its

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Improved amorphous silicon passivation layer for heterojunction solar cells with post-deposition plasma treatment

Cited by 19 publications

References 35 publications

Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Silicon Heterojunction Solar Cells and p‐type Crystalline Silicon Wafers: A Historical Perspective

Bifunctional CO₂ Plasma Treatment at the i/p Interface Enhancing the Performance of Planar Silicon Heterojunction Solar Cells

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Improved amorphous silicon passivation layer for heterojunction solar cells with post-deposition plasma treatment

Cited by 19 publications

References 35 publications

Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Role of Hydrogen in the Electronic Properties of a-Si:H/c-Si Heterostructures

Silicon Heterojunction Solar Cells and p‐type Crystalline Silicon Wafers: A Historical Perspective

Bifunctional CO2 Plasma Treatment at the i/p Interface Enhancing the Performance of Planar Silicon Heterojunction Solar Cells

Contact Info

Product

Resources

About

Bifunctional CO₂ Plasma Treatment at the i/p Interface Enhancing the Performance of Planar Silicon Heterojunction Solar Cells