Thin-film polycrystalline silicon solar cells. Quarterly report No. 2, December 11, 1978-March 10, 1979

Technical Report · Tue May 01 04:00:00 EDT 1979

DOI:https://doi.org/10.2172/5840257· OSTI ID:5840257

Faughnan, B. W.; Blanc, J.; Redfield, D.

In the second quarter, 40 solar cells were fabricated on Wacker substrates. One series of cells was used to compare the effect on AM-1 parameters of making the cells from the center region or the edge region of the original 10 x 10-cm wafer. Another series tested the effect of varying the junction diffusion temperatue from 850 to 900/sup 0/C. In both cases the differences were not large, except for diffused junctions at 850/sup 0/C. Passivation of grain boundaries by heating in a plasma discharge containing atomic hydrogen was attempted on a number of cells. With one ion-implanted cell, which was poor to begin with, a 21% improvement in efficiency was obtained. However, on a number of other more efficient cells, there was no significant improvement. A variety of experimental techniques for studying polycrystalline silicon and the effects of grain boundaries were implemented this quarter. They include measurement of minority carrier lifetime, QE curves with and without bias light, QE measurements using a 150-..mu..m spot, within a grain and including a grain boundary, laser scans across grain boundaries, and deep-level spectroscopy by transient capacitance. These measurements allowed us to assess the effects of grain boundaries on solar-cell performance. The surface topography of etched and polished cells was studied by SEM. An SEM method of determining the crystallographic orientation of small grains, called electron channeling patterns (ECP), was developed.The phosphorus diffusion profiles in Wacker material inside a grain and including a grain boundary were measured by SIMS. The presence of small black inclusions in Wacker material was observed.

• Research Organization: RCA Labs., Princeton, NJ (USA)
• OSTI ID: 5840257
• Report Number(s): SAN-1876-2
• 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
360603 -- Materials-- Properties
CARRIER LIFETIME
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
CRYSTAL STRUCTURE
CRYSTALS
DESIGN
DIFFUSION LENGTH
DIRECT ENERGY CONVERTERS
EFFICIENCY
ELECTRIC DISCHARGES
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
ELEMENTS
FABRICATION
FILMS
FLUIDS
GRAIN BOUNDARIES
HYDROGEN
HYDROGENATION
INSPECTION
LASERS
LIFETIME
MICROSCOPY
MICROSTRUCTURE
MORPHOLOGY
NONMETALS
OPTICAL PROPERTIES
PASSIVATION
PERFORMANCE
PHOSPHORUS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
POLYCRYSTALS
RESEARCH PROGRAMS
SCANNING ELECTRON MICROSCOPY
SEMIMETALS
SILICON
SILICON SOLAR CELLS
SOLAR CELLS