Fabrication and characterization of quench-cast silicon for solar cell application
A new silicon ribbon casting process was developed at Source Technology Applied Metallurgicals, Inc. for use in the fabrication of low cost photovoltaic cells. This process, known as double roller quench casting, produces ribbon directly from silicon metal by pouring molten silicon into the nip of two counter-rotating chilled copper wheels. A polycrystalline silicon ribbon forms continuously and is later cut up to make individual solar cells. The ribbon material has a grain size of 50 to 400 microns. The grains are columnar and oriented perpendicular to the ribbon surface. Polishing and etching reveals a number of etch pits, which are believed to be caused by defects formed during rapid cooling of the material. The resistivity of the quench cast material is higher than the feedstock by a factor of 1.5 to 4. Low temperature mobility and resistivity measurements do not show the presence of grain boundary potential barriers. Reduced mobility of p-type material indicates a large number of scattering centers probably caused by the intra-grain defects. Solar cells fabricated on quench cast material have efficiencies as high as 8.7% under simulated AM1 spectrum. The minority carrier diffusion length as measured by spectral response was found to be on the order of 10 microns. An open circuit voltage of 484 mV was measured and is consistent with the diffusion length.
- Research Organization:
- Basel Univ. (Switzerland)
- OSTI ID:
- 6126437
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Related Subjects
36 MATERIALS SCIENCE
SILICON
CASTING
SILICON SOLAR CELLS
EFFICIENCY
MANUFACTURING
QUENCHING
DIRECT ENERGY CONVERTERS
ELEMENTS
EQUIPMENT
FABRICATION
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SOLAR CELLS
SOLAR EQUIPMENT
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture