SILICON

Silicon makes up 28% of the earth's crust by weight, and is the second most abundant element, exceeded only by Oxygen.
It is found most as silicon oxides such as sand, quartz, rock, crystal, flint, jasper, and opal. It is also found in minerals such as asbestos, feldspar, clay and mica.

Uses of Silicon:

Oranball.gif (924 bytes)Silicon in Mechanical Materials:

Single-crystal silicon is being used in a variety of new commercial products because of its excellent mechanical properties. Recent trends show that the use of silicon as mechanical material is inexpensive, batch-fabricated, high-performance sensors, and transducers which are easily interfaced with rapidly proliferating microprocessor. Using silicon will significantly alter the way we thin about all types of miniature devices and components. 

Oranball.gif (924 bytes)Silicon used in making glass:

Glass manufacturing is a 10-billion -dollar-per-day industry in the United States. The major component of glass is almost pure quarts sand. A wide variety of glass properties can be produced by varying the glass composition. Colored glass is make by adding a few percents of colored transition metal oxide. Photochromic eyeglasses have a small amount of silver chloride dispersed throughout and trapped in the glass.

Oranball.gif (924 bytes)Quartz:

quartz.JPG (11678 bytes) Quartz is used for a variety of things but is most used n the making of jewelry. Quartz pendents can be worn as a fine piece of quartz crystal jewelry or used in meditation and can be used to improve the quality of your everyday life.

Oranball.gif (924 bytes)Silicon and sand:

silicon.JPG (10934 bytes) Sand is an industrial term used for sand or easily desegregated sandstone with a very high percentage of quartz (silica) grains. The Red Deer River deposits are being developed using on-site screening and washing facilities for the production of white sand for the golf course bunker market. Beneficiation tests conducted on Cretaceous and Ordovician Winnipeg Formation sands demonstrate that the sands can be effectively upgraded by attrition scrubbing, magnetic separation, acid leaching and calculation. The resulting product is similar, or better than, the Quintus grade of Unimin Corporation. The impurities represent less than 0.01 per cent of the product.


Oranball.gif (924 bytes)Other Common Uses of Silicon:

 

Oranball.gif (924 bytes)Major Use of Silicon:  Crystalline Silicon

c2.gif (33387 bytes) Crystalline Silicon is likely to continue to dominate PV markets at least through the year 2000. This silicon has high efficiency and stability, competitive cost, and a good track record it plays a dominant role in both domestic and international markets. Today’s crystalline silicon is more efficient than ever before. The laboratory cells that were made from single-crystal silicon have measured as high as 24 percent. The research involved focuses on the reducing of electricity. The low-cost silicon used by industry has lower efficiencies than that of pure silicon used in the laboratory. NREL’s crystal growth research emphasizes the approach to silicon growth. This work will help with the "next-generation" technologies. These methods will produce material more quickly, reproduce energy and material consumption, and help improve the conversion efficiency of cells made from silicon. There are four approaches being taken to the crystalline technology: thin-layer silicon on glass, silicon filament solar cells, and innovative single-crystal silicon growth from cold crucibles.

AstroPower Inc. hopes investors will take the time to look at the solar-cell manufacturing process. The Silicon-Film process operates at continuous high speeds, and produces large crystalline silicon sheets used in cells, and uses cheaper silicon in its production. Researchers are also working with industry to push the efficiency limits of pure-silicon-based devices. By increasing the efficiency of crystalline materials through improved processing is a major goal of the PV Program’s Crystalline Silicon Research Cooperative. NREL researchers are studying the role of defects and impurities in crystalline silicon.

Researchers are working to develop a fundamental understanding of the role of defects and impurities in crystalline silicon (c-Si) materials, as well as how they relate to device processing. Researchers are working to ameliorate the deleterious effects of defects and impurities in c-Si solar cells. This is very important, because the defects and impurities are more common in the lower-cost silicon feedstock and c-Si growth methods used in industry. We are working to generate and characterize samples with controlled concentrations of dopants, impurities, and defects, and we're studying methods to remove impurities and minimize the effects of the defects.

 

Oranball.gif (924 bytes)Bibliography:

Hoover’s Company Capsules, (1997 March). AstroPower, Inc. Available: http://www.ipocentral.com/ml-ipo/55538ml.html.

1997 March. Crystalline Silicon. Available: http://www.eren.doe.gov/pv/crystal.html.

1997 March. About Conversion Efficiencies. Available: http://www.eren.doe.gov/pv/conveff.html.

1997 March. Solar Energy and Silicon Technology. Available: http://spigot.amu.edu/de95/node34.html.

1997 March. Crystalline Silicon. Available: http://www.nrel.gov/pv/crystalgrowth.html.

McQuarrie,D. and Rock, P. (1985) Descriptive Chemistry. New York: W. H. Freeman and Company.

 

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