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Radiation-Hard, High Efficiency InP/InN Tandem Cells

Award Information

Department of Defense
Missile Defense Agency
Award ID:
Program Year/Program:
2004 / STTR
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
Spire Corporation
One Patriots Park Bedford, MA 01730-2396
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Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Phase 1
Fiscal Year: 2004
Title: Radiation-Hard, High Efficiency InP/InN Tandem Cells
Agency / Branch: DOD / MDA
Contract: HQ0006-04-C-7104
Award Amount: $99,931.00


Spire proposes to investigate InP/InN tandem solar cells for applications where extreme radiation-hardness is needed. Indium phosphide (InP) has proven itself as a radiation-hard cell material, and indium nitride (InN) has shown superior radiation resistance to 2MeV protons. InP (1.34 eV) and InN (0.7eV) bandgaps allow current-matching (38 mA/cm2) under the AM0 spectrum, enabling two-terminal operation. We will investigate use of a pseudomorphic InGaP window to boost InP top cell efficiency from its current 19% one-sun AM0 level to 22%. We describe a process that allows the InP top cell to be undisturbed by dislocations from the InN growth. The 0.7eV InN bottom cell has an upper efficiency limit of ~9% AM0; however, the growth of InN would introduce substantial dislocations, and its efficiency would likely be about 4%. However, the dislocations should not compromise the InN radiation hardness, and we believe that the proposed research should lead to tandem space cells with efficiencies of ~26% (1 sun AM0, 25C) which would be flat in power output to fluences beyond 1e16 1MeV electrons/cm2.

Principal Investigator:

Steven Wojtczuk
Senior Scientist

Business Contact:

Mark C. Little
CEO, Spire Biomedical, Inc.
Small Business Information at Submission:

One Patriots Park Bedford, MA 01730

EIN/Tax ID: 042457335
Number of Employees:
Woman-Owned: No
Minority-Owned: No
HUBZone-Owned: No
Research Institution Information:
Lawrence Berkeley Laboratory
One Cyclotron Road
Berkeley, CA 94720
Contact: Joel Ager
Contact Phone: (510) 486-6715
RI Type: Nonprofit college or university