Silicon materials task of the Low-Cost Solar Array Project (Phase IV). Effects of impurities and processing on silicon solar cells. Nineteenth quarterly report, April 1980-June 1980

Technical Report · Tue Jul 01 04:00:00 EDT 1980

DOI:https://doi.org/10.2172/5198361· OSTI ID:5198361

Hopkins, R H; Davis, J R; Rohatgi, A; Campbell, R B; Rai-Choudhury, P; Hanes, M H; Mollenkopf, H C; McCormick, J R

The overall objective of this program is to define the effects of impurities, various thermochemical processes, and any impurity-process interactions upon the performance of terrestrial solar cells. The results of the study form a basis for silicon producers, wafer manufacturers, and cell fabricators to develop appropriate cost-benefit relationships for the use of less pure, less costly solar grade silicon. Nine 4 ohm-cm p type silicon ingots were grown and evaluated in support of the experimental program this quarter. Of these, three were polycrystalline ingots doped with Cr, Mo, and V, respectively, produced under conditions which successfully eliminated the metal-rich inclusions formed when growth of these heavily-doped specimens was attempted during the last quarter. Evaluation of polycrystalline ingots doped to the mid 10/sup 13/ cm/sup -3/ range with Ti or V showed little evidence for grain boundary segregation. Deep level spectroscopy on both as-grown wafers and solar cells showed little variation in impurity concentration from place to place across the ingot regardless of the presence of grain boundaries or other structural features. Deep level spectroscopy was also used to monitor the electrically active impurity concentrations in ingots to be used for process studies, aging experiments, and high efficiency cells. The basic aspects of a model to describe efficiency behavior in high efficiency cells have been formulated and a computer routine is being implemented for back field type devices to analyze the functional relationships between impurity concentrations and cell performance.

• Research Organization: Westinghouse Research and Development Center, Pittsburgh, PA (USA); Hemlock Semiconductor Corp., MI (USA)
• DOE Contract Number: NAS-7-100-954331
• OSTI ID: 5198361
• Report Number(s): DOE/JPL/954331-80/11
• 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
CARBON
CHEMICAL ANALYSIS
CHROMIUM
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
CRYSTALS
DIRECT ENERGY CONVERTERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EQUIPMENT
FLUIDS
GRAIN BOUNDARIES
IMPURITIES
METALS
MICROSTRUCTURE
MOLYBDENUM
NONMETALS
OXYGEN
PERFORMANCE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLYCRYSTALS
REFRACTORY METALS
RESEARCH PROGRAMS
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTROSCOPY
TITANIUM
TRACE AMOUNTS
TRANSITION ELEMENTS
VANADIUM