Thin films of silicon on metallurgical silicon substrates. Phase II. Quarterly project report, March 1-May 31, 1978

Technical Report · Thu Jun 01 04:00:00 EDT 1978

DOI:https://doi.org/10.2172/5558904· OSTI ID:5558904

Chu, T. L.

The objectives of this contract are to investigate thin films of silicon on metallurgical silicon substrates and to demonstrate an AM1 efficiency of 10% 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, the fabrication and characterization of solar cells, the reduction of grain boundary effects, and preliminary investigations of the stability of thin film polycrystalline silicon solar cells. The use of the acid extraction and phosphorus pentoxide treatment techniques for the removal of iron from metallurgical silicon has been continued. Metallurgical silicon purified by both techniques has been used to prepare substrates for the deposition of the active region of solar cells. Solar cells of 9 cm/sup 2/ area have been prepared from planar substrates recrystallized from acid-extracted and phosphorus pentoxide treated metallurgical silicon. The heat treatment of the deposited solar cell structures has been found to be essential to obtain good characteristics. Using chemically deposited tin-dioxide films as antireflection coatings, the best cell has an AM1 efficiency of 9.5% at room temperature. Preliminary work on the effects of thermal and optical stress on the characteristics of thin film polycrystalline silicon solar cells indicates that they are stable under conditions for terrestrial applications.

• Research Organization: Southern Methodist Univ., Dallas, TX (USA)
• OSTI ID: 5558904
• Report Number(s): SAN-1285-T1
• 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
EPITAXY
EQUIPMENT
FABRICATION
FILMS
GRAIN BOUNDARIES
HEAT TREATMENTS
JUNCTIONS
MICROSTRUCTURE
OXIDES
OXYGEN COMPOUNDS
P-N JUNCTIONS
PERFORMANCE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLYCRYSTALS
PURIFICATION
RECRYSTALLIZATION
RESEARCH PROGRAMS
SEMICONDUCTOR JUNCTIONS
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTRAL RESPONSE
STABILITY
STRESSES
SUBSTRATES
TIN COMPOUNDS
TIN OXIDES