Ultra-High-Efficiency, Monolithic, Dual-Junction Solar Cells

Essential Research, Inc.(ERI)

Cleveland, OH

Lattice-mismatched multi-junction high efficiency solar cells

• Developed proprietary, step-graded buffer layer scheme that allows the growth of very low defect density, lattice- mismatched InGaAs on GaAs and InP substrates
• Fabricated high efficiency, metamorphic, single-junction 1.1 eV InGaAs, 1.62 eV InGaP, and dual junction 1.62 eV / 1.1 eV InGaP/InGaAs solar cells on GaAs substrates using the buffer layer scheme

• This SBIR served as a basis for an Air Force contract to develop a triple-junction, lattice-mismatched solar cell.Efficiencies of 25% were achieved with a goal of 31%
• Private capital from ERI and loans totaling $750K were used to establish and operate independent production facilities
• Received $100K from commercial business to date from related areas
• ERI increased employees by 5 to a total of 9 people

• These types of solar cells will be used by both NASA and DOD in various programs
• A new technology area has been established for multi- junction cells-the lattice mismatched multi-junction cells

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