Seed-assisted growth of high-quality multi-crystalline silicon in directional solidification

• Published in: Journal of crystal growth Vol. 386; pp. 52 - 56
• Main Authors: Zhu, Didi, Ming, Liang, Huang, Meiling, Zhang, Zhaoyu, Huang, Xinming
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.01.2014; Elsevier
• Subjects: A1. Directional solidification; A1. Dislocation; A2. Seed-assisted; A3. Uniform grain sizes; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Crucibles; Crystal growth; Directional solidification; Dislocations; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; General studies of phase transitions; Grains; Growth from melts; zone melting and refining; Materials science; Methods of crystal growth; physics of crystal growth; Minority carriers; Nucleation; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Silicon; Solidification; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation; A3. Uniform grain sizes; A2. Seed-assisted; A1. Directional solidification; A1. Dislocation; Solar cells; Crystal growth; Grain size; Nucleation; Grain growth; Directional solidification; Crucibles; Crystal seeds; Minority carriers; Dislocations; Dislocation density; Carrier lifetime; Growth mechanism; Silicon; Crystal growth from melts
• ISSN: 0022-0248; 1873-5002
• DOI: 10.1016/j.jcrysgro.2013.09.051

An approach to grain control using seed-assisted growth in directional solidification (DS) is reported in this paper. Proper multi-crystalline silicon seeds at the bottom of the crucible provided numerous fine nucleation points for the controlled grain growth in an optimized hot-zone. Low dislocation density was observed with large numbers of uniform small grains in the silicon ingot, although the grain size increased with crystal growth. Crystals produced using seed-assisted growth showed a higher and more uniform minority carrier lifetime with a much lower dislocation multiplication rate. A higher average solar cell conversion efficiency of about 0.5% in absolute value was obtained in the seed-assisted grown silicon in comparison with that in the seedless silicon under the same cell fabrication process. •Multi-crystalline silicon seeds for externally seeded growth process were performed.•We carried out a study in an optimized hot-zone for seed-assisted growth.•Uniform grains sizes with low dislocation density and propagation rate was obtained.•Minority carrier lifetime with high values and uniform distribution can be achieved.•The solar cells with high conversion efficiency were achieved in the seeded ingot.