Development of high-efficiency solar cells on silicon web. Second quarterly progress report, July-September 1984

Technical Report · Wed Nov 21 04:00:00 EST 1984

DOI:https://doi.org/10.2172/6086353· OSTI ID:6086353

Rohatgi, A.; Meier, D. L.; Campbell, R. B.; Schmidt, D. N.; Rai-Choudhury, P.

The major objective of the work reported is to improve web base material with a goal toward obtaining solar cell efficiencies in excess of 18% (AM1). The program consists of the investigation of carrier loss mechanisms in web silicon, development of techniques to reduce carrier recombination in web, and web cell fabrication using effective surface passivation. The effect of stress on web cell performance has been investigated. Preliminary data indicate that stress has no appreciable influence on the minority-carrier diffusion length in the as-grown web crystals. A web solar cell manufacturing run has also been completed. Fill factors were low and cell efficiencies were only in the 13 to 15% range. The impurity-twin-plane interaction has been investigated by conducting DLTS measurements as a function of depth on titanium-doped web crystal. Initial results indicate that the grown-in titanium impurity tends to pile up near the twin plane. Electron beam induced current (EBIC) measurements have been performed on beveled web samples to detect any recombination activity at the twin planes within the web material. Preliminary measurements indicate that twin planes in web show higher recombination activity compared to the rest of the bulk; however, this recombination activity can vary appreciably along the length of the web crystal. (LEW)

• Research Organization: Westinghouse Research and Development Center, Pittsburgh, PA (USA)
• DOE Contract Number: NAS-7-100-956786
• OSTI ID: 6086353
• Report Number(s): DOE/JPL/956786-84/2; ON: DE85005938
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
140501* -- Solar Energy Conversion-- Photovoltaic Conversion
ALLOYS
CRYSTAL GROWTH METHODS
DENDRITIC WEB GROWTH METHOD
DIFFUSION LENGTH
DIMENSIONS
DIRECT ENERGY CONVERTERS
DOPED MATERIALS
EQUIPMENT
LENGTH
MATERIALS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
RECOMBINATION
RESIDUAL STRESSES
SILICON SOLAR CELLS
SOLAR CELLS
SOLAR EQUIPMENT
STRESSES
TITANIUM ADDITIONS
TITANIUM ALLOYS
TWINNING