Currently the cost of solar grade silicon accounts for approximately one third of the total solar cell cost, therefore a new silicon refining process is being proposed with the goal of lowering the cost of producing solar grade silicon.
In this new process, Si-Cu alloys were used as the silicon source. One to one molar ratio H2-HCl gas mixtures were used as transport agents to extract Si out from the Si-Cu alloy at about 300-700oC, with following reaction taking place:
Si+3HCl(g)=HSiCl3(g)+H2(g)
While at about 1000-1300oC, pure Si deposits onto a hot silicon rod according to:
Si+3HCl(g)=HSiCl3(g)+H2(g)
The role of the copper in the alloy was to trap impurities in the Si and catalyze the gas solid reaction. A study on determining the rate limiting step and impurity behavior was done. A possible silicon extraction reaction mechanism was also addressed.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/25713 |
| Date | 03 January 2011 |
| Creators | LI, Mark Xiang |
| Contributors | Utigard, Torstein A. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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