This technology describes a method for producing high quality polycrystalline silicon (poly-Si) thin-films from amorphous silicon (a-Si). Poly-Si thin-films are an attractive alternative to single-crystal silicon (c-Si) as conventional c-Si solar cells, despite having high conversion efficiencies, are fragile, expensive, and resource intensive. The polycrystalline silicon films produced using this technology are compatible with a variety of substrate materials including glass, metal foil, and plastic. They also have potential for use in other types of silicon-based thin-film electronics.
Surface-oriented polycrystalline silicon thin-films prepared through flash lamp annealing
The poly-crystalline silicon thin-films described in this technology are produced by exposing amorphous silicon films to a pulse of white light -- a process known as Flash Lamp Annealing (FLA). This creates a film with a mix of liquid and crystalline domains. The crystalline domains then act as seed crystals and align the melted silicon as it solidifies. This method can produce films that contain large, surface-oriented grains. Most importantly, the density of defects within the grains is low, allowing for more efficient charge capture and conduction throughout the film. This method can be scaled for large-area or flexible substrates and optimized for thin-film electronics applications, including solar cells and thin-film transistors (TFT). This technology has been demonstrated to achieve efficiencies as high as 5.4%.
Lead Inventor:
James S. Im, Ph.D..
Applications:
- Thin-film solar cells
- Large-scale solar arrays
- Thin-film electronics
- Microelectronics
- Thin-film transistors (TFT)
- Silicon solar cells
Advantages:
- Low intragrain defect densities
- Large grain size
- Control of crystallographic orientation
- Requires less silicon feedstock than conventional methods
- Adaptable for large-scale applications
- Can be used in combination with other silicon crystallization methods such as sequential lateral solidification (SLS)
- Compatible with flexible substrates
Patent information:
Tech Ventures Reference: IR M08-067
Related Publications:
- Omori K, Ganot GS, Chung U-J, Chitu AM, Limanov AB, and Im JS. "Flash-Lamp-Induced Lateral Solidification of Thin Si Films". MRS Proceedings, 2011;(1321) mrss11-1321-a03-04 (2011) doi:10.1557/opl.2011.930
*Hazair S, van der Wilt PC, Deng Y, Chung U-J, Limanov AB, and Im JS. "Nucleation-Initiated Solidification of Thin Si Films," MRS Proceedings, 2006; (979 0979-HH11-22 doi:10.1557/PROC-979-0979-HH11-22
*Van Gestel, D, Chahal, M., van der Wilt, PC, Yu Q, Gordon, I. Im, JS, Poortmans, J. "Thin-film polycrystalline silicon solar cells with low intragrain defect density made via laser crystallization and epitaxial growth" Photovoltaic Specialists Conference (PVSC), 2010 35th IEEE. 2010 20-25 June; 000279-000282
- Teplin, CW. "Towards Low-cost >15% Efficient Film c-Si Solar Cells: Progress & Challenges" Optics InfoBase conference papers. 2012 Nov 11-14; ISBN: 978-1-55752-952 7