Boron removal from silicon melt by gas blowing technique
Author:
Hoseinpur Arman1, Andersson Stefan2, Müller Michael3, Tang Kai2, Safarian Jafar1
Affiliation:
1. Department of Materials Science and Engineering, Norwegian University of Science and Technology (NTNU) , 7034 Trondheim , Norway 2. SINTEF Industry , 7465 Trondheim , Norway 3. Institute of Energy and Climate Research, IEK-2, Forschungszentrum Jülich GmbH , Wilhelm-Johnen-Straße , 52428 Jülich , Germany
Abstract
Abstract
Due to the detrimental effects of boron (B) on the efficiency of silicon (Si) photovoltaic cells, complete boron removal from Si is necessary to produce solar grade Si (SoG–Si, with a maximum limit of 0.1 ppmw boron). Gas refining is a promising technique for boron removal from Si, in which the thermodynamic equilibrium never establishes. Hence, by starting from any B concentration in the melt, the required limit for SoG–Si will be achieved. This research is devoted to studying the refractory interactions’ effect with melt and the chamber atmosphere on boron removal. For this purpose, gas refining experiments were carried out in alumina and graphite crucibles with H2 and H2–3% H2O refining gases. Gas refining in Ar, He, and continuous vacuuming conditions were also carried out to study the effect of chamber atmosphere. The gas refining results are supported by the characterization of the evaporated species by molecular beam mass spectroscopy (MBMS) technique. The MBMS measurements indicated that the boron evaporation occurs by the formation of the volatile species BH
x
, BO
y
, and B
z
H
x
O
y
compounds. Most of these compounds are already known in the literature. However, HBO, HBOH, and AlBO (in the case of alumina refractories) were measured experimentally in this work. Results indicate that the evaporation of B in the form of AlBO
x
compounds leads to higher mass transfer coefficients for boron removal in alumina crucibles. Density-functional theory (DFT) and coupled cluster calculations are carried out to provide a thermodynamic database for the gaseous compounds in the H–B–O–Al system, including enthalpy, entropy, and C
P values for 21 compounds.
Publisher
Walter de Gruyter GmbH
Subject
Physical and Theoretical Chemistry,Mechanics of Materials,Condensed Matter Physics,General Materials Science
Reference63 articles.
1. Wilson, G. M., M. Al-Jassim, W. K. Metzger, S. W. Glunz, P. Verlinden, G. Xiong, et al. The 2020 photovoltaic technologies roadmap. Journal of Physics D: Applied Physics, Vol. 53, No. 49, 2020, id. 493001. 10.1088/1361-6463/ab9c6a. 2. IRENA. Future of Solar Photovoltaic: Deployment, Investment, Technology, Grid Integration and Socio-Economic Aspects, 2019. 3. Yang, D. Handbook of photovoltaic silicon, handbook of photovoltaic silicon, Springer Berlin Heidelberg, Berlin, Heidelberg, 2019, pp. 1–841. 4. Philips, D. S. and W. Warmuth. Photovoltaics report. PSE Conferences and Consulting Gmbh, Freiburg, 2019. 5. Thomas, S., M. Barati, and K. Morita. A review of slag refining of silicon alloys. Jom, Vol. 73, No. 1, 2021, pp. 282–292. 10.1007/s11837-020-04474-0.
Cited by
3 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献
|
|