Influence of the feedstock purity on the solar cell efficiency

Meyer, Sylke; Wahl, Stefanie; Молчанов, А. М.; Neckermann, Kristin; Möller, Christian; Lauer, Kevin; Hagendorf, Christian

doi:10.1016/j.solmat.2014.04.003

Cited by 17 publications

(6 citation statements)

References 2 publications

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“…Integrated circuits accounted for 70% of domestic gallium consumption, and optoelectronic devices accounted for 30% [14]. However, even very small amounts of impurities, such as Cu, Pb, Fe, Mg, Zn, and Cr, which are always present in current large-scale, commercial-quality gallium, can degrade or limit the electrical properties [15]. Traditional refining methods, such as electrolysis and combined processes, have been used in the past to remove these impurities to obtain high-purity gallium [16].…”

Section: Introductionmentioning

confidence: 99%

A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

Pan

Zhang

et al. 2018

Materials

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As one of the critical raw materials, very pure gallium is important for the semiconductor and photoelectric industry. Unfortunately, refining gallium to obtain a purity that exceeds 99.99999% is very difficult. In this paper, a new, facile and efficient continuous partial recrystallization method to prepare gallium of high purity is investigated. Impurity concentrations, segregation coefficients, and the purification effect were measured. The results indicated that the contaminating elements accumulated in the liquid phase along the crystal direction. The order of the removal ratio was Cu > Mg > Pb > Cr > Zn > Fe. This corresponded to the order of the experimentally obtained segregation coefficients for each impurity: Cu < Mg < Pb < Cr < Zn < Fe. The segregation coefficient of the impurities depended strongly on the crystallization rate. All observed impurity concentrations were substantially reduced, and the purity of the gallium obtained after our refinement exceeded 99.99999%.

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Section: Introductionmentioning

confidence: 99%

A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

Pan

Zhang

et al. 2018

Materials

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“…[18] Therefore, developing new processes with proper control of phosphorus in SoG-Si is important. [19] Nowadays, up to 0.2 ppmw of phosphorus in Si is accepted as the limit for SoG-Si production, which could be reduced in the future if higher efficiencies are required. [20] Many research works have been carried out in the recent years on removal of P from Si, [8,9,[21][22][23][24][25][26][27][28] and many of them were focused on vacuum refining.…”

Section: Introductionmentioning

confidence: 99%

On the Phosphorus Evaporation from Liquid Silicon by Knudsen Effusion Mass Spectrometry

Hoseinpur

Sergeev

Müller

et al. 2022

Metall Mater Trans B

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Silicon refining for solar applications is intensively on demand, and removal of phosphorus from Si is one of the most challenging steps. Evaporation of P from liquid Si in a vacuum refining process is the most efficient method for P removal from Si, and this research deals with the insight mechanisms of P evaporation from liquid Si. In this research, the gaseous species evaporating from the dilute liquid solutions of phosphorus in silicon were studied experimentally, and it was shown that phosphorus evaporates in the form of P, P2, P4, P3, SiP, Si2P, Si3P, and SiP2 at elevated temperatures. Except P and P2, the other molecules were detected experimentally for the first time, and Si3P was detected as a new compound in the gas phase. Knudsen effusion mass spectrometry technique was applied to characterize the evaporation of phosphorus from liquid Si samples containing 100, 1250, and 3000 ppmw phosphorus. The evaporation of phosphorus from liquid Si was studied by isothermal and polythermal experiments, up to 1840 °C. The vapor pressures of various P-containing molecules (P, P2, P4, SiP, Si2P) at 1442 °C were measured as a function of phosphorus fraction in liquid silicon. Results indicated that a major part of the phosphorus evaporates in the form of silicon phosphides and P4, especially when the sample temperature exceeds 1750 °C. When initial phosphorus was 100 ppmw, about 71 pct of phosphorus evaporation was by means of silicon phosphides and P4. The mechanisms of phosphorus evaporation from liquid Si are proposed, which depend on the melt composition and temperature. It occurs through phosphorus species evaporation independently or via the decomposition of transient silicon phosphides at the surface or through the direct evaporation of silicon phosphides at the melt surface.

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“…This raw material increases the cost of the solar cells due to the fact that the raw material is the most expensive constituent. Our goal is to find a way to reduce this cost by using a cheap raw material, such as the upgraded metallurgical (UMG) silicon as solar-grade silicon (SoG) [1]. This silicon is less expensive than polysilicon due to its quality according to the impurities level; but it can be used for solar cells production with proper production process [2].…”

Section: Introductionmentioning

confidence: 99%

3D numerical simulation with experimental validation of a traveling magnetic field stirring generated by a Bitter coil for silicon directional solidification process

Hiba

Nouri

Hachani

et al. 2022

IOP Conf. Ser.: Mater. Sci. Eng.

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Silicon is the most widely used raw material in photovoltaic industry; however, the quality of the silicon photovoltaic solar cells depends on the quality of the raw material (i.e. metallurgical silicon or poly-silicon) and the solidification methods used for the production of the silicon ingot from which the solar cells are produced. This study is related to how improve the quality of the final ingot in the directional solidification process; it is necessary to control the impurity segregation of silicon raw material during the processing. This control can be accomplished by adding an electromagnetic Bitter coil which can generate an external traveling magnetic field (TMF) stirring to control the hydrodynamic flow of silicon melt during the solidification process without contaminating it. To carry out this study, we used a Bridgman vertical directional solidification furnace, equipped with a cylindrical Bitter coil stirrer used in order to have the control of the silicon melt convection on the principal parameters of the solidification process, such as the growth rate, the thermal gradient and the natural convection of silicon melt. For the electromagnetic, heat exchange and silicon melt flow modelling, we used 3D numerical Multiphysics coupled models. Parallel to the numerical results we carried out experimental investigations relating to the characterization of the electromagnetic parameters. This study shows a promising effect of the applied traveling magnetic field on the final ingot quality; indeed, we have the ability to control the silicon melt flow which can affect the thermal configuration, the solidification interface shape and the segregation of impurities by changing the electric current input configuration of the Bitter coil stirrer.

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Influence of the feedstock purity on the solar cell efficiency

Cited by 17 publications

References 2 publications

A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

A Facile and Low-Cost Method to Produce Ultrapure 99.99999% Gallium

On the Phosphorus Evaporation from Liquid Silicon by Knudsen Effusion Mass Spectrometry

3D numerical simulation with experimental validation of a traveling magnetic field stirring generated by a Bitter coil for silicon directional solidification process

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