Liquid phase crystallized silicon – A holistic absorber quality assessment

Sonntag, Paul; Bokalič, Matevž; Preissler, Natalie; Amkreutz, Daniel; Rech, Bernd; Topič, Marko

doi:10.1016/j.solmat.2017.08.019

Cited by 4 publications

(10 citation statements)

References 25 publications

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“…However, aside from grain-boundary recombination, regions with a high amount of stacking faults and recombination activity (black circles in figure 2) are present. A detailed investigation by lightbeam induced current (LBIC, [Sonntag17b]) and electron-beam induced current mappings (EBIC, [Seifert11]) revealed a significantly lower effective diffusion length below 2 micrometers in these regions. So far no dependency between grain orientation and recombination activity was determined.…”

Section: Formation and Properties Of Lpc Absorbersmentioning

confidence: 99%

Progress in and potential of liquid phase crystallized silicon solar cells

et al. 2018

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Liquid phase crystallization of silicon (LPC-Si) offers great potential for high-quality Si films and a cost effective fabrication technique for thin crystalline silicon solar cells on glass. In this work, we report on the progress on LPC-silicon at HZB in the past years. Beginning with a brief description of the fabrication process, we summarize the work on the different contact systems developed for these absorbers before focusing on the interdigitated back contact architecture on which the highest efficiencies were reported. State-of-the art cells form the basis for a detailed discussion of the status of this technology. We investigate the current loss mechanisms and explore the potential for further improvement. Finally, based on this comprehensive quality assessment, we develop a roadmap to increase the cell efficiencies to wafer-equivalent values.

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Section: Formation and Properties Of Lpc Absorbersmentioning

confidence: 99%

Progress in and potential of liquid phase crystallized silicon solar cells

et al. 2018

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“…To conclude, under the assumption that the capture cross sections of defects present at the IL/LPC‐Si interfaces are similar to values published for silicon wafers coated with SiN x and SiO 2 , S eff,front is well below 100 cm s −1 with both the O/N and the O/N/O IL stack. In a recent study, measured quantum efficiency curves of LPC‐Si solar cells based on the O/N/O IL stack were simulated and S eff,front = 200 cm s −1 was found . The lower values obtained in this work could be explained by the fact that the MIS structures cover an area of around 1 mm 2 and thus, fit within one grain (Figure ).…”

Section: Resultsmentioning

confidence: 59%

“…The employment of other characterization techniques, such as capacitance‐voltage ( C – V ) measurements, is not straight forward since the glass substrate blocks one side of the interface of interest. The surface recombination velocity ( S eff,front ) at the buried front‐side IL/LPC‐Si interface is commonly determined indirectly by fitting measured solar cell parameters using simulation tools such as AFORS‐HET, ASPIN3, and TCAD Sentaurus™ . Corresponding results obtained for various IL stacks adjacent to LPC‐Si are listed in Table .…”

Section: Introductionmentioning

confidence: 99%

Passivation of Liquid‐Phase Crystallized Silicon With PECVD‐SiN_x and PECVD‐SiN_x/SiO_x

Preissler

Amkreutz

Dulanto

et al. 2018

Physica Status Solidi (a)

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Silicon nitride (SiN x ) and silicon oxide (SiO x ) grown with plasma-enhanced chemical vapor deposition are used to passivate the front-side of liquid-phase crystallized silicon (LPC-Si). The dielectric layer/LPC-Si interface is smooth and layers are well-defined as demonstrated with transmission electron microscopy. Using electron energy loss spectroscopy a thin silicon oxynitride is detected which is related to oxidation of the SiN x prior to the silicon deposition. The interface defect state density (D it ) and the effective fixed charge density (Q IL,eff ) are obtained from high-frequency capacitance-voltage measurements on developed metal-insulator-semiconductor structures based on SiO x /SiN x /LPC-Si and SiO x /SiN x /SiO x /LPC-Si sequences. Charge transfer across the SiN x /LPC-Si interface is observed which does not occur with the thin SiO x between SiN x and LPC-Si. The SiO x /SiN x /LPC-Si interface is characterized by Q IL,eff > 10 12 cm À2 and D it,MG >10 12 eV À1 cm À2 . With SiO x /SiN x /SiO x stack, both parameters are around one order of magnitude lower. Based on obtained Q IL,eff and D it (E) and capture cross sections for electrons and holes of σ n ¼ 10 À14 cm s À1 and σ p ¼ 10 À16 cm s À1 , respectively, a front-side surface recombination velocity in the range of 10 cm s À1 at both interfaces is determined using the extended Shockley-Read-Hall recombination model. Results indicate that field-effect passivation is strong, especially with SiO x /SiN x stack.

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“…There is a clear trend showing increasing average V OC with thicker a‐Si(i) as well as the inclusion of hydrogen plasma treatment (Figure ). Bulk doping (shown in x ‐axis) also has an influence on V OC but previous studies covering 3–16 × 10 16 and 2–17 × 10 16 cm −3 showed only a 20 mV change in average V OC . Therefore, Figure primarily shows the effect of a‐Si:H(i) passivation.…”

Section: Resultsmentioning

confidence: 94%

“…The effective diffusion length of minority carriers have been previously calculated to be up to 79 μm in passivated areas but less than 20 μm in poorly passivated areas . The isolation gap between the hole and electron contact can be assumed to be around 60 μm . Therefore the metal‐Si contact and the unpassivated isolation gap may act as recombination sites for charge carriers generated at the periphery of the illuminated area.…”

Section: Resultsmentioning

confidence: 99%

Toward High Solar Cell Efficiency with Low Material Usage: 15% Efficiency with 14 μm Polycrystalline Silicon on Glass

et al. 2020

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Liquid‐phase‐crystallized silicon (LPC‐Si) is a bottom‐up approach to creating solar cells with the potential to avoid material loss and energy usage in wafer slicing techniques. A desired thickness of silicon (5–40 μm) is crystallized with a line‐shaped energy source, which is a laser, herein. The first part reports the efforts to optimize amorphous silicon contact layers for better surface passivation. The second part covers laser firing on the electron contact. It enables a controllable trade‐off between charge collection and fill factor (FF) by creating a low resistance contact, while preserving a‐Si:H (i) passivation in other areas. Short‐circuit current density (JSC) is observed to be up to 33:1 mA cm−2, surpassing all previously reported values for this technology. Open‐circuit voltage (VOC) of up to 658 mV also exceeded every previous value published at a low bulk doping concentration (1 × 1016 cm−3). Laser firing reduced JSC by 0:6 mA cm−2 on average but improved the FF by 22.5% absolute on average, without any significant effect on VOC. Collectively, these efforts have helped in achieving a new in‐house record efficiency for LPC‐Si of 15.1% and show a potential to reach 16% efficiency in the near future with optimization of series resistance.

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Liquid phase crystallized silicon – A holistic absorber quality assessment

Cited by 4 publications

References 25 publications

Progress in and potential of liquid phase crystallized silicon solar cells

Progress in and potential of liquid phase crystallized silicon solar cells

Passivation of Liquid‐Phase Crystallized Silicon With PECVD‐SiN_x and PECVD‐SiN_x/SiO_x

Toward High Solar Cell Efficiency with Low Material Usage: 15% Efficiency with 14 μm Polycrystalline Silicon on Glass

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Liquid phase crystallized silicon – A holistic absorber quality assessment

Cited by 4 publications

References 25 publications

Progress in and potential of liquid phase crystallized silicon solar cells

Progress in and potential of liquid phase crystallized silicon solar cells

Passivation of Liquid‐Phase Crystallized Silicon With PECVD‐SiNx and PECVD‐SiNx/SiOx

Toward High Solar Cell Efficiency with Low Material Usage: 15% Efficiency with 14 μm Polycrystalline Silicon on Glass

Contact Info

Product

Resources

About

Passivation of Liquid‐Phase Crystallized Silicon With PECVD‐SiN_x and PECVD‐SiN_x/SiO_x