Voltage-matched, two-terminal, GaAs (AlGaAs)/CuInSe/sub 2/ tandem solar cells

Mechanically stacked tandem solar cells based on GaAs thin-film single-crystal top cells and CuInSe/sub 2/ (CIS) bottom cells were developed to meet the weight and radiation-resistance requirements of advanced spacecraft power systems. Efficiencies over 23% have been demonstrated with these cells in a four-terminal configuration. In order to use the device as a direct replacement for conventional single-junction cells with existing array designs. a two-terminal, voltage-matched tandem cell with 8 cm/sup 2/ area has been designed and fabricated. Tandem cells with efficiencies over 20% have been demonstrated with this design. AlGaAs high-bandgap cells have been demonstrated with efficiency over 17% for future AlGaAs/ClS tandem cells capable of higher end-of-life efficiency. The performance of the two-terminal tandem cells and the AlGaAs high-bandgap cell are described.< >