High Power Density III-V Cells for Ultralight Aircraft

Award Information
Agency: Department of Defense
Branch: Air Force
Contract: N/A
Agency Tracking Number: 28260
Amount: $543,309.00
Phase: Phase II
Program: SBIR
Awards Year: 1996
Solicitation Year: N/A
Solicitation Topic Code: N/A
Solicitation Number: N/A
Small Business Information
One Patriots Park, Bedford, MA, 01730
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Dr Steven J. Wojtczuk
 (617) 275-6000
Business Contact
Phone: () -
Research Institution
Ultralight III-V solar cells are proposed to extend the mission duration of unmanned air vehicles (UAVs). Silicon panels used with an already flying UAV have panel power densities of 400 W/kg, using 15% AM0 thin (110 um) silicon cells. Here we propose using even thinner (8 um), higher efficiency (25% AM0), InGaP/GaAs tandem cells, bonded to thin coverglasses, to greatly increase the cell power density. Cells are first fabricated on thicker substrate wafers, and these wafers are later removed once the cells are bonded to thin (3 mil) CMG coverglasses. Panel power densities almost four times greater (1500 W/kg) than that offered by silicon should result from the higher efficiency and much lighter weight of the proposed cells. In Phase I, single-junction (10% AM0) GaAs cells would be made and bonded to 3 mil CMG coverglass with RTV adhesive. The substrates would then be removed with a selective etch. The wafer backs would then be metalized, and completed cells would be available at the end of Phase I for evaluation. In Phase I, a design study would also be performed to identify the best technology (e.g. adhesives vs. electrostatic bonding, epitaxial liftoff vs. selective etching) to pursue in Phase II. In Phase II, tandem cells would be made, and the technology identified as best in the Phase I study would be developed in a process suitable for large areas and high-volume manufacturing.

* Information listed above is at the time of submission. *

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