arXiv subjects

Hasan Hüseyin Canar

Publications and source records attributed to Hasan Hüseyin Canar.

2 recordsLinked to original sources

arXiv2026

Production of Upgraded Metallurgical Grade (UMG) silicon for a low-cost high-efficiency and reliable PV technology

UMG-Si has the potential to reduce the cost of PV technology and to improve its environmental profile. In this contribution, we summarize the extensive work made in the research and development of UMG technology for PV, which has led to the demonstration of UMG-Si as a competitive alternative to polysilicon for the production of high-efficiency multicrystalline solar cells and modules. The tailoring of the processing steps along the complete Ferrosolar's UMG-Si manufacturing value chain has been addressed, commencing with the purification stage that results in a moderately compensated material due to the presence of phosphorous and boron. Gallium is added as a dopant at the crystallization stage to obtain a uniform resistivity profile 1 Ohm*cm along the ingot height. Defect engineering techniques based on phosphorus diffusion gettering have been optimized to improve the bulk electronic quality of UMG-Si wafers. Black silicon texturing, compatible with subsequent gettering and surface passivation, has been successfully implemented. Industrial-type BSF and PERC solar cells have been fabricated, achieving cell efficiencies in the range of those obtained with conventional polysilicon substrates. TOPCon solar cell processing key steps have also been tested to further evaluate the potential of the material in advanced device architectures beyond PERC. Degradation mechanisms related to light exposure and operation temperature have been shown not to be significant in UMG PERC solar cells when a regeneration step is implemented, and PV modules with several years of outdoor operation have demonstrated similar performance to reference ones based on poly-Si. LCA has been carried out to evaluate the environmental impact of UMG-based PV technology when compared to the poly-Si-based one, considering different scenarios both for the manufacturing sites and the PV installations.

cond-mat.mtrl-sci↗

arXiv2022

High carrier lifetimes in UMG multicrystalline wafers after P- diffusion compatible with high-efficiency cell structures

High-quality multicrystalline Upgraded Metallurgical Grade Silicon (UMG-Si) offers significant advantages over conventional polysilicon-based PV technology, associated to lower cost, lower energy budget and lower carbon footprint. The aim of this study is twofold: on the one hand, to ascertain the efficiency potential of solar cells based on this material in terms of carrier lifetime; and on the other hand, to explore, as a result of that, the adoption of high-efficiency cell architectures by establishing an effective rear-side passivation scheme for the implementation of passivated emitter rear contact (PERC) devices. The carrier lifetime and the surface passivation efficacy are investigated for different passivating layer configurations after single and double P-diffusion gettering processes. Layer stacks consisting of Al2O3, SiOxNy and a-SiNx:H capping overlayers have been optimized, on industrial size, saw-damage-etched UMG wafers and results compared to those obtained using reference iodine-ethanol (IE) passivation. Diagnosis based on minority carrier lifetime and implied Voc (iVoc) measurements helped monitor the impact of parameter optimization on wafer quality, particularly after firing processes. Carrier lifetimes over 600 us at 10^15 cm-3 injection level as well as up to 790 us locally have been measured in UMG-Si wafers passivated with IE after a Phosphorus Diffusion Gettering (PDG), demonstrating the suitability of the material for high-efficiency cell architectures. Values higher than 300 us have been obtained with Al2O3-based passivation layers for gettered UMG wafers, with implied Voc values up to 710 mV. These record-breaking lifetimes and iVoc figures obtained with p-type multicrystalline UMG-Si material demonstrate a significant upgrading of its electronic quality by means of industry-scalable technical processes.

cond-mat.mtrl-sci↗