High-Performance and Traditional Multicrystalline Silicon: Comparing Gettering Responses and Lifetime-Limiting Defects
Author(s)
Ekstrom, Kai E.; Autruffe, Antoine; Lai, Barry; Stokkan, Gaute; del Canizo, Carlos; Castellanos, Sergio; Jensen, Mallory Ann; Morishige, Ashley Elizabeth; Hofstetter, Jasmin; Yen, Patricia; Buonassisi, Anthony; ... Show more Show less
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In recent years, high-performance multicrystalline silicon (HPMC-Si) has emerged as an attractive alternative to traditional ingot-based multicrystalline silicon (mc-Si), with a similar cost structure but improved cell performance. Herein, we evaluate the gettering response of traditional mc-Si and HPMC-Si. Microanalytical techniques demonstrate that HPMC-Si and mc-Si share similar lifetime-limiting defect types but have different relative concentrations and distributions. HPMC-Si shows a substantial lifetime improvement after P-gettering compared with mc-Si, chiefly because of lower area fraction of dislocation-rich clusters. In both materials, the dislocation clusters and grain boundaries were associated with relatively higher interstitial iron point-defect concentrations after diffusion, which is suggestive of dissolving metal-impurity precipitates. The relatively fewer dislocation clusters in HPMC-Si are shown to exhibit similar characteristics to those found in mc-Si. Given similar governing principles, a proxy to determine relative recombination activity of dislocation clusters developed for mc-Si is successfully transferred to HPMC-Si. The lifetime in the remainder of HPMC-Si material is found to be limited by grain-boundary recombination. To reduce the recombination activity of grain boundaries in HPMC-Si, coordinated impurity control during growth, gettering, and passivation must be developed. Keywords: Defects; dislocation recombination activity; dislocations; eccentricity variation; high-performance multicrystalline silicon (HPMC-Si); minority-carrier lifetime; photovoltaics; recombination; synchrotron
Date issued
2016-04Department
Massachusetts Institute of Technology. Department of Mechanical EngineeringJournal
IEEE Journal of Photovoltaics
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Citation
Castellanos, Sergio et al. “High-Performance and Traditional Multicrystalline Silicon: Comparing Gettering Responses and Lifetime-Limiting Defects.” IEEE Journal of Photovoltaics 6, 3 (May 2016): 632–640 © 2016 IEEE
Version: Author's final manuscript
ISSN
2156-3381
2156-3403