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Diffusion lengths in irradiated N/P InP-on-Si solar cellsIndium phosphide (InP) solar cells were made on silicon (Si) wafers (InP/Si) by to take advantage of both the radiation-hardness properties of the InP solar cell and the light weight and low cost of Si wafers. The InP/Si cell application is for long duration and/or high radiation orbit space missions. Spire has made N/P InP/Si cells of sizes up to 2 cm by 4 cm with beginning-of-life (BOL) AM0 efficiencies over 13% (one-sun, 28C). These InP/Si cells have higher absolute efficiency and power density after a high radiation dose than gallium arsenide (GaAs) or silicon (Si) solar cells after a fluence of about 2e15 1 MeV electrons/sq. cm. In this work, we investigate the minority carrier (electron) base diffusion lengths in the N/P InP/Si cells. A quantum efficiency model was constructed for a 12% BOL AM0 N/P InP/Si cell which agreed well with the absolutely measured quantum efficiency and the sun-simulator measured AM0 photocurrent (30.1 mA/sq. cm). This model was then used to generate a table of AM0 photocurrents for a range of base diffusion lengths. AM0 photocurrents were then measured for irradiations up to 7.7e16 1 MeV electrons/sq. cm (the 12% BOL cell was 8% after the final irradiation). By comparing the measured photocurrents with the predicted photocurrents, base diffusion lengths were assigned at each fluence level. A damage coefficient K of 4e-8 and a starting (unirradiated) base electron diffusion length of 0.8 microns fits the data well. The quantum efficiency was measured again at the end of the experiment to verify that the photocurrent predicted by the model (25.5 mA/sq. cm) agreed with the simulator-measured photocurrent after irradiation (25.7 mA/sq. cm).
Document ID
19960045577
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Wojtczuk, Steven
(Spire Corp. Bedford, MA United States)
Colerico, Claudia
(Spire Corp. Bedford, MA United States)
Summers, Geoffrey P.
(Naval Research Lab. Washington, DC United States)
Walters, Robert J.
(Naval Research Lab. Washington, DC United States)
Burke, Edward A.
(Burke (Edward A.) Woburn, MA United States)
Date Acquired
August 17, 2013
Publication Date
February 1, 1996
Publication Information
Publication: Space Photovoltaic Research and Technology 1995
Subject Category
Energy Production And Conversion
Accession Number
96N32480
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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