Recombination in ingot cast silicon solar cells

• Published in: Physica status solidi. A, Applications and materials science Vol. 208; no. 4; pp. 760 - 768
• Main Authors: Rinio, Markus, Yodyungyong, Arthit, Keipert-Colberg, Sinje, Borchert, Dietmar, Montesdeoca-Santana, Amada
• Format: Journal Article
• Language: English
• Published: Berlin WILEY-VCH Verlag 01.04.2011; WILEY‐VCH Verlag; Wiley-VCH
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; dislocations; Energy; Exact sciences and technology; gettering; Interaction between different crystal defects; gettering effect; multicrystalline; Natural energy; Photovoltaic conversion; Physics; solar cell; Solar cells. Photoelectrochemical cells; Solar energy; Structure of solids and liquids; crystallography; Solar cells; Dislocation density; Annealing; Impurities; Defect recombination; Silicon; Minority carriers; Phosphorus additions; Quantum yield; Hydrogenation; Ingot
• DOI: 10.1002/pssa.201084022
• ISSN: 1862-6300

Minority carrier recombination is studied in multicrystalline ingot cast silicon solar cells. The normalized recombination strength Γ of dislocations is obtained by correlating topograms of the internal quantum efficiency (IQE) with those of the dislocation density ρ. Γ is obtained by fitting an extended theory of Donolato to the experimental data. The measured Γ‐values vary significantly between adjacent dislocation clusters and correlate with the spatial pattern of the dislocations. All Γ‐values are strongly dependent on the parameters of the solar cell process. The influence of phosphorus diffusion and hydrogenation is shown. After solidification of the silicon, impurities from the crucible enter the ingot and deteriorate its border regions during cooling to room temperature. These deteriorated border regions can be significantly improved by an additional low temperature anneal that is applied after phosphorus diffusion. The experiments indicate that the mechanism of the anneal is external phosphorus gettering into the emitter.