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Title: Wide-bandgap heterojunction window layers and optical confinement for high-efficiency silicon solar cells

Abstract

In order to improve the efficiency of silicon solar cells, minority carrier recombination must be reduced. Designs for solar cells which minimize recombination are discussed. To reduce surface recombination, use of a heterojunction structure with a wide-bandgap semiconductor lattice-matched to the silicon was explored. Heterojunction windows of zinc sulfide were fabricated and tested, and measurements of solar cell open circuit voltage, dark current, and short-wavelength quantum efficiency confirm that the surface recombination velocity is reduced from that of the bare surfaces. In order to reduce bulk recombination, a very thin cell is proposed, with a new geometrical optical confinement (light trapping) system to maintain high values of short-circuit current despite the lower cell thickness. Analysis of this design indicates that the efficiency of light trapping is extremely high, with trapped optical pathlengths of better than 50 times the width of the cell. Finally, improvements in solar cell performance require non-destructive techniques for measuring the lifetime of minority carriers in the initial wafers as well as in finished cells. A new method of directly measuring the carrier recombination in silicon was demonstrated.

Authors:
Publication Date:
Research Org.:
Brown Univ., Providence, RI (USA)
OSTI Identifier:
5232865
Resource Type:
Miscellaneous
Resource Relation:
Other Information: Thesis (Ph. D.)
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; SILICON SOLAR CELLS; DESIGN; EFFICIENCY; CARRIER DENSITY; OPTICAL PROPERTIES; PERFORMANCE; RECOMBINATION; DIRECT ENERGY CONVERTERS; EQUIPMENT; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; PHYSICAL PROPERTIES; SOLAR CELLS; SOLAR EQUIPMENT; 140501* - Solar Energy Conversion- Photovoltaic Conversion

Citation Formats

Landis, G A. Wide-bandgap heterojunction window layers and optical confinement for high-efficiency silicon solar cells. United States: N. p., 1988. Web.
Landis, G A. Wide-bandgap heterojunction window layers and optical confinement for high-efficiency silicon solar cells. United States.
Landis, G A. Fri . "Wide-bandgap heterojunction window layers and optical confinement for high-efficiency silicon solar cells". United States.
@article{osti_5232865,
title = {Wide-bandgap heterojunction window layers and optical confinement for high-efficiency silicon solar cells},
author = {Landis, G A},
abstractNote = {In order to improve the efficiency of silicon solar cells, minority carrier recombination must be reduced. Designs for solar cells which minimize recombination are discussed. To reduce surface recombination, use of a heterojunction structure with a wide-bandgap semiconductor lattice-matched to the silicon was explored. Heterojunction windows of zinc sulfide were fabricated and tested, and measurements of solar cell open circuit voltage, dark current, and short-wavelength quantum efficiency confirm that the surface recombination velocity is reduced from that of the bare surfaces. In order to reduce bulk recombination, a very thin cell is proposed, with a new geometrical optical confinement (light trapping) system to maintain high values of short-circuit current despite the lower cell thickness. Analysis of this design indicates that the efficiency of light trapping is extremely high, with trapped optical pathlengths of better than 50 times the width of the cell. Finally, improvements in solar cell performance require non-destructive techniques for measuring the lifetime of minority carriers in the initial wafers as well as in finished cells. A new method of directly measuring the carrier recombination in silicon was demonstrated.},
doi = {},
url = {https://www.osti.gov/biblio/5232865}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1988},
month = {1}
}

Miscellaneous:
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