Thin films of silicon on low-cost substrates. Annual report, September 1, 1976-August 31, 1977

Technical Report · Thu Sep 01 04:00:00 EDT 1977

OSTI ID:6407107

Chu, T L

The objective of this program is to investigate the fabrication of low cost thin film solar cells of relatively high efficiency and long life. Efforts during this year have been directed to (1) the purification of metallurgical silicon, (2) the preparation of metallurgical silicon substrates, (3) the deposition and characterization of silicon films on metallurgical silicon substrates, (4) the properties of polycrystalline silicon p-n junctions on metallurgical silicon substrates, and (5) the fabrication and characterization of silicon solar cells on purified metallurgical silicon substrates. Emphasis was directed to the characterization of the properties of silicon films and solar cells relevant to the optimization of the deposition process. Metallurgical silicon has been purified by a combination of chemical treatment and unidirectional solidification, and the purified material was unidirectionally solidifed on graphite to yield substrates for the deposition of silicon films and solar cells. The properties of epitaxial films, including grain boundaries, have been studied. The analysis of the electrical characteristics of polycrystalline p-n junctions indicates that the carrier recombination at grain boundaries may be included into that in the space charge region in the two-exponential model. Large area (30 cm/sup 2/) solar cells with AM1 efficiencies of 7.5% have been produced, and their spectral response, minority carrier diffusion length, dopant profile, etc. have been investigated.

• Research Organization: Southern Methodist Univ., Dallas, TX (USA)
• DOE Contract Number: AC03-76ET20410
• OSTI ID: 6407107
• Report Number(s): DOE/ET/20410-T4
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
CARBON
CHARGE CARRIERS
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CRYSTAL STRUCTURE
CRYSTALS
DATA
DEPOSITION
DIFFUSION LENGTH
DIMENSIONS
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRICAL PROPERTIES
ELEMENTS
EPITAXY
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
GRAIN BOUNDARIES
GRAPHITE
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
JUNCTIONS
LENGTH
MICROSTRUCTURE
NONMETALS
NUMERICAL DATA
OPTIMIZATION
P-N JUNCTIONS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLYCRYSTALS
PURIFICATION
RECOMBINATION
SEMICONDUCTOR JUNCTIONS
SEMIMETALS
SILANES
SILICON
SILICON COMPOUNDS
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPACE CHARGE
SPECTRAL RESPONSE
SUBSTRATES
SURFACE COATING