Silicon materials task of the low cost solar array project (Phase III). Effects of impurities and processing on silicon solar cells. Sixteenth quarterly report, July 1979-September 1979

Technical Report · Mon Oct 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/5600955· OSTI ID:5600955

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

The objective of this program is to determine how thermal processes, impurities, and impurity-process interactions affect the properties of silicon and the performance of terrestrial solar cells made from silicon. The Phase III effort encompasses five major topics, several of which represent new directions for our work: (1) examination of the interaction of impurities with processing treatments, (2) generation of a data base and modeling of impurity effects in n-base solar cells, (3) extension of previous p-base studies to include impurities likely to be introduced during silicon production, refining or crystal growth, (4) a consideration of the potential impact of anisotropic (nonuniform) impurity distribution in large Czochralski and ribbon solar cells and, (5) a preliminary investigation of the permanence of impurity effects in silicon solar cells. Important experimental results were obtained in five areas during this past quarter: (1) the impact of HCl gettering on Mo and Ti doped low resistivity silicon was assessed, (2) diffusion profiles were established for Ti and Mo after 1100/sup 0/C gettering treatments, (3) a correlation was identified between the electrically-active impurity concentration and the metallurgical concentration of several impurities in as-grown ingots, (4) cell and diode measurements verified that no significant anisotropy effects due to Cu or Fe in large diameter CZ ingots, or due to Ti and V in wide silicon web crystals occur, and (5) aging data for Cr indicate a more rapid depreciation in cell performance with time than for Mo or Ti doped cells. A detailed description of the results and analyses of the observed behavior is presented. (WHK)

• Research Organization: Westinghouse Electric Corp., Pittsburgh, PA (USA). Research and Development Center
• DOE Contract Number: NAS-7-100-954331
• OSTI ID: 5600955
• Report Number(s): DOE/JPL/954331-8
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ABSORPTION SPECTROSCOPY
AGING
ALLOYS
CARBON
CHROMIUM
CHROMIUM ADDITIONS
CHROMIUM ALLOYS
COPPER
CRYOGENIC FLUIDS
CRYSTAL GROWTH METHODS
CZOCHRALSKI METHOD
DIFFUSION
DIRECT ENERGY CONVERTERS
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
ELEMENTS
EQUIPMENT
FILL FACTORS
FLUIDS
GETTERING
IMPURITIES
IRON
MANGANESE
MASS SPECTROSCOPY
METALS
MOLYBDENUM
NICKEL
NONMETALS
OXYGEN
PERFORMANCE
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
PROCESSING
REFRACTORY METALS
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
SPECTROSCOPY
THERMOCHEMICAL PROCESSES
TITANIUM
TRANSITION ELEMENTS
VANADIUM
ZIRCONIUM