Silicon materials task of the low cost solar array project (Part 2). First Quarterly report, 1 October 1975--31 December 1975. Research report 76-9C4-SIMAT-R1

Technical Report · Fri Feb 20 04:00:00 EST 1976

DOI:https://doi.org/10.2172/7281261· OSTI ID:7281261

Hopkins, R. H.; Davis, J. R.; Rai-Choudhury, P.; Blais, P. D.; McCormick, J. R.

The objective of this program, Part 2 of the Silicon Materials Task, is to develop and define purity requirements for solar cell grade (SG) silicon material by evaluating the effects of specific impurities and impurity levels on the performance of silicon solar cells. The basic approach of the program is to establish, as unambiguously as possible, what concentrations of the impurities commonly found in silicon starting material (metallurgical grade silicon) can be tolerated in silicon crystals produced by both the standard Czochralski and the dendritic-web sheet (rapid growth) methods without degrading solar cell performance. The program is on schedule in all elements. Specifically the growth, evaluation, solar cell fabrication and testing are completed for the baseline boron-doped Czochralski material. Cell efficiencies are in the 11 to 13 percent range (AM1). The growth of six first generation Czochralski crystals (boron doping plus Cr, Mn, Cu, Ni, V, and Ti) is completed. Solar cell measurements on four of the first doubly-doped ingots indicate that Cr and Mn seriously degrade cell performance at the 10/sup 15/ cm/sup -3/ doping level while neither Ni nor Cu produce any significant reduction in cell efficiency. The results for Ni can be rationalized on the basis of its known gettering properties. The results for Cu are surprising and may indicate that precipitation of Cu or gettering during diffusion have rendered it inactive as a recombination center. (WDM)

• Research Organization: Dow Corning Corp., Hemlock, Mich. (USA)
• OSTI ID: 7281261
• Report Number(s): ERDA/JPL/954331-76/1
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
36 MATERIALS SCIENCE
360104 -- Metals & Alloys-- Physical Properties
CRYSTAL GROWTH
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELEMENTS
FABRICATION
IMPURITIES
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS