Recombination activity of grain boundaries in high-performance multicrystalline Si during solar cell processing

• Published in: Journal of applied physics Vol. 123; no. 5; pp. 1 - 6
• Main Authors: Adamczyk, Krzysztof, Søndenå, Rune, Stokkan, Gaute, Looney, Erin, Jensen, Mallory, Lai, Barry, Rinio, Markus, Di Sabatino, Marisa
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 07.02.2018; American Institute of Physics (AIP)
• Subjects: Diffusion layers; Electron backscatter diffraction; Fysik; Gettering; Grain boundaries; Heat treatment; Heterojunctions; high-performance multicrystalline silicon; Light beams; Light diffraction; MATERIALS SCIENCE; multicrystalline; Photovoltaic cells; Physics; Quantum efficiency; recombination; Silicon; Solar cells; Wafers; X-ray fluorescence
• ISSN: 0021-8979; 1089-7550; 1089-7550
• DOI: 10.1063/1.5018797

In this work, we applied internal quantum efficiency mapping to study the recombination activity of grain boundaries in High Performance Multicrystalline Silicon under different processing conditions. Wafers were divided into groups and underwent different thermal processing, consisting of phosphorus diffusion gettering and surface passivation with hydrogen rich layers. After these thermal treatments, wafers were processed into heterojunction with intrinsic thin layer solar cells. Light Beam Induced Current and Electron Backscatter Diffraction were applied to analyse the influence of thermal treatment during standard solar cell processing on different types of grain boundaries. The results show that after cell processing, most random-angle grain boundaries in the material are well passivated, but small-angle grain boundaries are not well passivated. Special cases of coincidence site lattice grain boundaries with high recombination activity are also found. Based on micro-X-ray fluorescence measurements, a change in the contamination level is suggested as the reason behind their increased activity.