Thin films of silicon on metallurgical silicon substrates: Phase II. Quarterly project report No. 2, December 1, 1977--28 February 1978

Technical Report · Wed Mar 01 04:00:00 EST 1978

OSTI ID:7043654

Chu, T L

The objectives of this study are to investigate thin films of silicon on metallurgical silicon substrates and to demonstrate an AM1 efficiency of 10 percent for large area (30 cm/sup 2/) thin film silicon solar cells by August 1979. Efforts during the past quarter have been directed to the purification of metallurgical silicon, the preparation of substrates, and the fabrication and characterization of solar cells. Iron and aluminum are major impurities in metallurgical silicon; the usefulness of the acid extraction technique and phosphorus pentoxide gettering technique for the removal of iron has been investigated in detail. Substrates for the deposition of the active region of solar cells have been prepared from metallurgical silicon purified by both techniques using the unidirectional solidification technique. Large area (30 cm/sup 2/) solar cells have been prepared from acid-leached planar substrates by the thermal reduction of trichlorosilane containing appropriate dopants. Chemically deposited tin-dioxide films were used as antireflection coatings. The best cell has an AM1 efficiency of 7.5 percent at room temperature. The characteristics of solar cells in the temperature range of -40 degrees C to 100 degrees C have been investigated. Preliminary work on the effects of grain boundaries by the EBIC technique has been carried out. The feasibility of using polycrystalline silicon films for the fabrication of MOS type solar cells has also been investigated.

• Research Organization: Southern Methodist Univ., Dallas, Tex. (USA)
• OSTI ID: 7043654
• Report Number(s): SAN-1285-4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360601 -- Other Materials-- Preparation & Manufacture
ANTIREFLECTION COATINGS
CHALCOGENIDES
COATINGS
CRYSTAL STRUCTURE
CRYSTALS
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRICAL PROPERTIES
ELEMENTS
FABRICATION
FILMS
GETTERING
GRAIN BOUNDARIES
IMPURITIES
IRON
JUNCTIONS
METALS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
P-N JUNCTIONS
PERFORMANCE TESTING
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLYCRYSTALS
PURIFICATION
SEMICONDUCTOR JUNCTIONS
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS
SPECTRAL RESPONSE
SUBSTRATES
TEMPERATURE EFFECTS
TESTING
TIN COMPOUNDS
TIN OXIDES
TRANSITION ELEMENTS