Influence of Barrier and Doping Type on the Open-Circuit Voltage of Liquid Phase-Crystallized Silicon Thin-Film Solar Cells on Glass

Haschke, Jan; Amkreutz, Daniel; Frijnts, Tim; Kühnapfel, Sven; Hänel, T.; Rech, Bernd

doi:10.1109/jphotov.2015.2412453

Cited by 22 publications

(36 citation statements)

References 18 publications

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“…So far, the investigations of the IL/LPC‐Si interface have been restricted to indirect measurements of the solar cell parameters open circuit voltage and internal quantum efficiency and it was found that the IL/LPC‐Si interface has a major impact on the solar cell performance . For the direct analysis of the passivation quality at the IL/LPC‐Si interface, the defect state density at the interface ( D it in eV −1 cm −2 ) as well as the effective charge density in the IL ( Q IL,eff in cm −2 ) are crucial parameters .…”

Section: Introductionmentioning

confidence: 99%

Interface passivation of liquid‐phase crystallized silicon on glass studied with high‐frequency capacitance–voltage measurements

Preissler

Töfflinger

Shutsko

et al. 2016

Physica Status Solidi (a)

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The passivation quality at the interface between dielectric interlayer (IL) stacks and liquid-phase crystallized silicon (LPC-Si) was investigated by means of high-frequency capacitance-voltage (C-V) measurements. The developed device structure was based on a molybdenum layer sandwiched between the glass substrate and the IL/LPC-Si stack. C-V curves were discussed in terms of hysteresis formation and capacitance relaxation. We varied the nitrogen and hydrogen content in the a-SiO x N y :H layer adjacent to the LPC-Si and studied the effects on the defect state density at the IL/LPC-Si interface (D it ) as well as on the effective charge density in the IL (Q IL,eff ). Both parameters are crucial for the analysis of chemical and field-effect passivation. Furthermore, the effect of an additional hydrogen plasma treatment (HPT) on D it and Q IL,eff was investigated. A Gaussian-like defect distribution at around 0.1 eV above the mid gap energy is significantly reduced by the additional HPT. With additional HPT, the lowest D it and highest Q IL,eff at mid gap, i.e., D it ¼ (3.5 AE 0.7) Â 10 11 eV À1 cm À2 and Q IL,eff ¼ (1.6 AE 0.3) Â 10 12 cm À2, correspond to the passivation by an a-SiO x N y :H layer with a low nitrogen and high hydrogen content.

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Section: Introductionmentioning

confidence: 99%

Interface passivation of liquid‐phase crystallized silicon on glass studied with high‐frequency capacitance–voltage measurements

Preissler

Töfflinger

Shutsko

et al. 2016

Physica Status Solidi (a)

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“…In 2011, an open circuit voltage ( V OC ) of 545 mV was realized on LPC‐Si. Since then, improved interlayer stacks and the use of n‐type absorber doping resulted in V OC values above 650 mV and a highest efficiency of 13.2% . All cells on LPC‐Si are backside contacted, as the glass side cannot be contacted.…”

Section: Introductionmentioning

confidence: 99%

Influence of the Frontside Charge Inversion Layer on the Minority Carrier Collection in Backside Contacted Liquid Phase Crystallized Silicon on Glass Solar Cells

et al. 2017

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External quantum efficiency and light beam induced current measurements were used to investigate backside contacted solar cells made on p‐type, liquid phase crystallized silicon on glass (LPC‐Si). Among other differences, these cells had either a SiOxNy or an Al2O3/SiO2 based frontside surface passivation (interlayer). From the measurements it was observed that the cell with the SiOxNy interlayer showed a charge carrier collection from below the absorber contact and from outside the cell area that is much larger than expected from the typical diffusion length in LPC‐Si. This was in contrast to the cell with the Al2O3/SiO2 interlayer, which showed the expected behavior. It was also observed that for the cell with the SiOxNy interlayer, both the collection outside and the collection inside the cell area were strongly bias light dependent. It is argued that these charge carriers collected from outside the cell area are collected through a frontside charge inversion layer. This was supported by an analysis of the measured wavelength and bias light dependence of the collection outside the cell area for the cell with the SiOxNy interlayer. The measured fixed charge density of the interlayer stack with the SiOxNy layer was used to estimate the sheet resistance of the frontside charge inversion layer and this sheet resistance could explain the bias light dependence of the collection outside the cell area. The fixed charge density was also used to simulate the excess carrier density dependence of effective surface recombination at the SiOxNy/c‐Si interface and these simulation results could explain the bias light dependence of the collection inside the cell area.

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“…[4][5][6]8,9 The type and stacking order of the silicon dielectric used in such an interlayer is vital for high open circuit voltage in solar cells using LPC-Si on glass. [4][5][6]8 In previous studies, however, the SiO x , SiN x , and/or silicon carbide layers investigated for solar cells were grown either by RF sputtering only 5−8 or in combination with plasma enhanced chemical vapor deposition (PECVD), 5 which requires more than one deposition vacuum chamber. Since the silicon absorber precursor for the LPC-Si test cells used in this study was grown by PECVD, an interlayer consisting of SiO x , SiN x , and/ or SiO x N y could be made in the same tool just by varying the precursor gas composition.…”

Section: Introductionmentioning

confidence: 99%

“…2, 18 It is now appreciated that surface passivation by a silicon dielectric combined with bulk passivation using a hydrogen plasma is necessary to increase the solar cell efficiency of thin ≤10 μm thick c-Si on glass. 6,8,9,19 However, thus far, the influence of the chemical composition and structure of the passivating silicon dielectric material in combination with an additional hydrogen passivation of the c-Si on glass has not been specifically investigated. Therefore, in this contribution, we study the influence of varying the deposition parameters of PECVD grown a-SiO x: H, a-SiN x :H, and a-SiO x N y :H on their chemical composition and structure.…”

Section: Introductionmentioning

confidence: 99%

Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass

Calnan

Gabriel

Rothert

et al. 2015

ACS Appl. Mater. Interfaces

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In this study, various silicon dielectric films, namely, a-SiOx:H, a-SiNx:H, and a-SiOxNy:H, grown by plasma enhanced chemical vapor deposition (PECVD) were evaluated for use as interlayers (ILs) between crystalline silicon and glass. Chemical bonding analysis using Fourier transform infrared spectroscopy showed that high values of oxidant gases (CO2 and/or N2), added to SiH4 during PECVD, reduced the Si-H and N-H bond density in the silicon dielectrics. Various three layer stacks combining the silicon dielectric materials were designed to minimize optical losses between silicon and glass in rear side contacted heterojunction pn test cells. The PECVD grown silicon dielectrics retained their functionality despite being subjected to harsh subsequent processing such as crystallization of the silicon at 1414 °C or above. High values of short circuit current density (Jsc; without additional hydrogen passivation) required a high density of Si-H bonds and for the nitrogen containing films, additionally, a high N-H bond density. Concurrently high values of both Jsc and open circuit voltage Voc were only observed when [Si-H] was equal to or exceeded [N-H]. Generally, Voc correlated with a high density of [Si-H] bonds in the silicon dielectric; otherwise, additional hydrogen passivation using an active plasma process was required. The highest Voc ∼ 560 mV, for a silicon acceptor concentration of about 10(16) cm(-3), was observed for stacks where an a-SiOxNy:H film was adjacent to the silicon. Regardless of the cell absorber thickness, field effect passivation of the buried silicon surface by the silicon dielectric was mandatory for efficient collection of carriers generated from short wavelength light (in the vicinity of the glass-Si interface). However, additional hydrogen passivation was obligatory for an increased diffusion length of the photogenerated carriers and thus Jsc in solar cells with thicker absorbers.

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Influence of Barrier and Doping Type on the Open-Circuit Voltage of Liquid Phase-Crystallized Silicon Thin-Film Solar Cells on Glass

Cited by 22 publications

References 18 publications

Interface passivation of liquid‐phase crystallized silicon on glass studied with high‐frequency capacitance–voltage measurements

Interface passivation of liquid‐phase crystallized silicon on glass studied with high‐frequency capacitance–voltage measurements

Influence of the Frontside Charge Inversion Layer on the Minority Carrier Collection in Backside Contacted Liquid Phase Crystallized Silicon on Glass Solar Cells

Influence of Chemical Composition and Structure in Silicon Dielectric Materials on Passivation of Thin Crystalline Silicon on Glass

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