Impact of doped microcrystalline silicon oxide layers on crystalline silicon surface passivation

Ding, Kaining; Aeberhard, Urs; Lambertz, Andreas; Smirnov, Vladimir; Holländer, B.; Finger, F.; Rau, Uwe

doi:10.1139/cjp-2013-0627

Cited by 10 publications

(4 citation statements)

References 18 publications

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“…This trend is independent of the microstructure being amorphous or nanocrystalline [51]. Accordingly, Ding et al [52] reported, for doped nc-SiO x :H layers, a similar oxygen content despite the strongly higher Fc of n-type films (above 60%) over p-type once (below 20%). This result suggests that the doping gas nature can influence the nanocrystalline evolution.…”

Section: Nanocrystalline Silicon Material: Properties and Challengesmentioning

confidence: 81%

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

et al. 2020

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Doped hydrogenated nanocrystalline (nc-Si:H) and silicon oxide (nc-SiOx:H) materials grown by plasma-enhanced chemical vapor deposition have favourable optoelectronic properties originated from their two-phase structure. This unique combination of qualities, initially, led to the development of thin-film Si solar cells allowing the fabrication of multijunction devices by tailoring the material bandgap. Furthermore, nanocrystalline silicon films can offer a better carrier transport and field-effect passivation than amorphous Si layers could do, and this can improve the carrier selectivity in silicon heterojunction (SHJ) solar cells. The reduced parasitic absorption, due to the lower absorption coefficient of nc-SiOx:H films in the relevant spectral range, leads to potential gain in short circuit current. In this work, we report on development and applications of hydrogenated nanocrystalline silicon oxide (nc-SiOx:H) from material to device level. We address the potential benefits and the challenges for a successful integration in SHJ solar cells. Finally, we prove that nc-SiOx:H demonstrated clear advantages for maximizing the infrared response of c-Si bottom cells in combination with perovskite top cells.

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Section: Nanocrystalline Silicon Material: Properties and Challengesmentioning

confidence: 81%

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

et al. 2020

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“…This is due to its broad range of optical and electrical properties, which can be tuned by varying deposition parameters: i.e., absorption coefficient, refractive index, optical band gap, and p-type and n-type doping, which allow it to make selective contacts. Doping films with phosphorus (n-type) has resulted in further improved conductivities, and hydrogen atoms in the mixture have resulted in effective defect passivation [5]. Nanocrystalline silicon oxide (nc-SiOx:H) consists of crystalline silicon nanoparticles embedded in an amorphous phase composed of silicon oxide (a-SiOx:H) and a-Si:H phases [6,7].…”

Section: Introductionmentioning

confidence: 99%

Development of n-Type, Passivating Nanocrystalline Silicon Oxide Films via Plasma-Enhanced Chemical Vapor Deposition

Kaur,

Olivares,

Roca i Cabarrocas

2024

Solar

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Nanocrystalline silicon oxide (nc-SiOx:H) is a multipurpose material with varied applications in solar cells as a transparent front contact, intermediate reflector, back reflector layer, and even tunnel layer for passivating contacts, owing to the easy tailoring of its optical properties. In this work, we systematically investigate the influence of the gas mixture (SiH4, CO2, PH3, and H2), RF power, and process pressure on the optical, structural, and passivation properties of thin n-type nc-SiOx:H films prepared in an industrial, high-throughput, plasma-enhanced chemical vapor deposition (PECVD) reactor. We provide a detailed description of the n-type nc-SiOx:H material development using various structural and optical characterization techniques (scanning electron microscopy (SEM), energy dispersive X-ray (EDX), Raman spectroscopy, and spectroscopic ellipsometry) with a focus on the relationship between the material properties and the passivation they provide to n-type c-Si wafers characterized by their effective carrier lifetime (τeff). Furthermore, we also outline the parameters to be kept in mind while developing different n-type nc-SiOx:H layers for different solar cell applications. We report a tunable optical gap (1.8–2.3 eV) for our n-type nc-SiOx:H films as well as excellent passivation properties with a τeff of up to 4.1 ms (implied open-circuit voltage (iVoc)~715 mV) before annealing. Oxygen content plays an important role in determining the crystallinity and hence passivation quality of the deposited nanocrystalline silicon oxide films.

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“…Noteworthy are the advantages as contact and/or window layer both in thin film and silicon wafer based heterojunction solar cells due to their lower (parasitic) absorption and higher conductivity. Alloying with oxygen (nc‐SiO x :H) helps to reduce parasitic absorption further and, moreover, reduces reflection of the incoming light in case of SHJ . The two‐phase character of this material permits to tune its optical and electrical properties in a wide range by varying the gas mixture, doping, and deposition conditions .…”

Section: Introductionmentioning

confidence: 99%

Nanocrystalline silicon emitter optimization for Si-HJ solar cells: Substrate selectivity and CO₂plasma treatment effect

Mazzarella

Kirner

Gabriel

et al. 2016

Phys. Status Solidi A

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We investigated hydrogenated nanocrystalline silicon (nc‐Si:H) films as doped emitter layers for silicon heterojunction solar cells. Firstly, we focused on the effect of the nc‐Si:H deposition conditions and film growth on the intrinsic hydrogenated amorphous silicon passivation layer ((i)a‐Si:H) underneath. Three different p‐doped emitters were compared: nc‐Si:H, nc‐SiOx:H, and a‐Si:H. We found that the nc‐Si:H and nc‐SiOx:H growth enhances the passivation of the epitaxy‐free (i)a‐Si:H layer, yielding implied open circuit voltages above 730 mV. Secondly, for (p)nc‐Si:H emitters, we observed a trade‐off between fill factor (FF) and open circuit voltage (Voc) by using two types of (i)a‐Si:H films. A slight epitaxy of the (i)layer seems to promote the rapid nucleation of nc‐Si:H, thereby positively affecting the FF (79.5%) and series resistance but reducing Voc (670 mV). Contrarily, on well‐passivating (i)a‐Si:H the nc‐Si:H nucleation is more difficult resulting in S‐shaped I–V curves, presumably due to low built‐in voltage and a poor emitter/TCO contact. To circumvent this dilemma, a CO2 plasma treatment is used to oxidize the a‐Si:H surface before the nc‐Si:H emitter deposition thereby enhancing nucleation. Accordingly, a FF of 74.5% with Voc of 727 mV is reached in the best device, yielding a conversion efficiency of 21%. HR‐TEM micrograph of the front layer stack of the solar cell. The image shows a region close to the valley between two pyramids. From bottom to top: c‐Si substrate, (i)a‐Si:H passivation layer showing epitaxially grown regions, (p)nc‐Si:H emitter layer, and In2O3:Sn (ITO). Yellow lines highlight layers and individual crystals. Silicon zone axis orientation is <101>.

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Impact of doped microcrystalline silicon oxide layers on crystalline silicon surface passivation

Cited by 10 publications

References 18 publications

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

Development of n-Type, Passivating Nanocrystalline Silicon Oxide Films via Plasma-Enhanced Chemical Vapor Deposition

Nanocrystalline silicon emitter optimization for Si-HJ solar cells: Substrate selectivity and CO₂plasma treatment effect

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Impact of doped microcrystalline silicon oxide layers on crystalline silicon surface passivation

Cited by 10 publications

References 18 publications

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

Versatility of Nanocrystalline Silicon Films: from Thin-Film to Perovskite/c-Si Tandem Solar Cell Applications

Development of n-Type, Passivating Nanocrystalline Silicon Oxide Films via Plasma-Enhanced Chemical Vapor Deposition

Nanocrystalline silicon emitter optimization for Si-HJ solar cells: Substrate selectivity and CO2plasma treatment effect

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Nanocrystalline silicon emitter optimization for Si-HJ solar cells: Substrate selectivity and CO₂plasma treatment effect