Surface passivation and heterojunction cells on Si (100) and (111) wafers using dc and rf plasma deposited Si:H thin films

Das, Ujjwal; Burrows, M.; Lu, Meijun; Bowden, Stuart; Birkmire, Robert W.

doi:10.1063/1.2857465

Cited by 112 publications

(77 citation statements)

References 8 publications

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“…7 In other words, a high level of hydrogenation of the c-Si surface is desired. 7 This is most often achieved during the deposition of the a-Si:H layers, which is typically done by PECVD and usually at low pressures, 28 although it has been shown that high pressures can yield good passivation as well. 29,30 Additionally, post-deposition annealing is frequently employed as a tool to further relax the a-Si:H nanostructure and accommodate migration of atomic Published by AIP Publishing.…”

Section: Introductionmentioning

confidence: 99%

“…122, 035302-1 H from the bulk of the a-Si:H towards the a-Si:H/c-Si interface. 28,31 Therefore, a sufficiently high hydrogen content in the film is generally preferred. 32 Secondly, the lowest defect density and best surface passivation is typically obtained by preparing dense a-Si:H films close to the amorphous-tocrystalline transition, while making sure that the film maintains fully amorphous.…”

Section: Introductionmentioning

confidence: 99%

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Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

Macco

Melskens

Podraza³

et al. 2017

Journal of Applied Physics

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Using an inductively coupled plasma, hydrogenated amorphous silicon (a-Si:H) films have been prepared at very low temperatures (<50 °C) to provide crystalline silicon (c-Si) surface passivation. Despite the limited nanostructural quality of the a-Si:H bulk, a surprisingly high minority carrier lifetime of ∼4 ms is demonstrated after a rapid thermal annealing treatment. Besides the excellent level of surface passivation, the main advantage of the low-temperature approach is the facile suppression of undesired epitaxial growth. The correlation between the a-Si:H nanostructure and the activation of a-Si:H/c-Si interface passivation, upon annealing, has been studied in detail. This yields a structural model that qualitatively describes the different processes that take place in the a-Si:H films during annealing. The presented experimental findings and insights can prove to be useful in the further development of very thin a-Si:H passivation layers for use in silicon heterojunction solar cells.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

Macco

Melskens

Podraza³

et al. 2017

Journal of Applied Physics

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“…6 The passivation of the crystalline silicon ͑c-Si͒ wafer surfaces is usually performed by very thin intrinsic amorphous silicon ͑a-Si:H͒ layers, deposited by rf plasma-enhanced chemical vapor deposition ͑PECVD͒ ͑Refs. 2, 3, and 5͒ or similar methods ͓direct-current PECVD, 3 hot-wire CVD ͑Ref. 4͔͒.…”

mentioning

confidence: 99%

“…Silicon heterojunction solar cells have a high conversion efficiency potential, [1][2][3][4][5] up to 23% to date. 6 The passivation of the crystalline silicon ͑c-Si͒ wafer surfaces is usually performed by very thin intrinsic amorphous silicon ͑a-Si:H͒ layers, deposited by rf plasma-enhanced chemical vapor deposition ͑PECVD͒ ͑Refs.…”

mentioning

confidence: 99%

The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality

Descoeudres¹,

Barraud²,

Bartlomé³

et al. 2010

Applied Physics Letters

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In silicon heterojunction solar cells, thin amorphous silicon layers passivate the crystalline silicon wafer surfaces. By using in situ diagnostics during plasma-enhanced chemical vapor deposition ͑PECVD͒, the authors report how the passivation quality of such layers directly relate to the plasma conditions. Good interface passivation is obtained from highly depleted silane plasmas. Based upon this finding, layers deposited in a large-area very high frequency ͑40.68 MHz͒ PECVD reactor were optimized for heterojunction solar cells, yielding aperture efficiencies up to 20.3% on 4 cm 2 cells.

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“…In this scenario, the silicon heterojunction (SHJ) solar cell technology could be a suitable choice for the photovoltaic industry. The hydrogenated amorphous silicon (a-Si:H) layers involved in SHJ devices can be deposited at temperatures below 300 ºC, typically by Plasma Enhanced Chemical Vapor Deposition (PECVD) [3]. There are also good alternatives to obtain high quality transparent conductive oxide (TCO) layers and metallic electrodes at similarly low temperatures [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Study of the Surface Recombination Velocity for Ultraviolet and Visible Laser-Fired Contacts Applied to Silicon Heterojunction Solar Cells

Morales-Vilches

Voz

Colina

et al. 2015

IEEE J. Photovoltaics

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Abstract-In this work we investigate the effect of the laser-firing process on the back surface passivation of p-type silicon heterojunction solar cells. For that purpose, two different nanosecond laser sources radiating at ultraviolet (355 nm) and visible (532 nm) wavelengths are employed. Firstly, we optimize the laser-firing process in terms of the electrical resistance of locally diffused point contacts. Specific contact resistance values as low as 0.91 mΩ⋅cm 2 and 0.57 mΩ⋅cm 2 are achieved for the visible and ultraviolet laser sources, respectively. In addition, the impact of the laser-firing process on the rear surface passivation is studied by analyzing the internal-quantum-efficiency curves of complete devices. Low surface recombination velocities in the range of 300 cm/s are obtained for the ultraviolet laser with a 1% fraction of contacted area. This value increases to about 700 cm/s for the visible laser, which indicates a significantly higher recombination at the contacted area. The best heterojunction solar cells with rear laser-fired contacts are obtained for the ultraviolet laser and reached a 17.5% conversion efficiency.

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Surface passivation and heterojunction cells on Si (100) and (111) wafers using dc and rf plasma deposited Si:H thin films

Cited by 112 publications

References 8 publications

Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

Correlating the silicon surface passivation to the nanostructure of low-temperature a-Si:H after rapid thermal annealing

The silane depletion fraction as an indicator for the amorphous/crystalline silicon interface passivation quality

Study of the Surface Recombination Velocity for Ultraviolet and Visible Laser-Fired Contacts Applied to Silicon Heterojunction Solar Cells

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