High efficiency 1.0 eV GaInAs bottom solar cell for 3-junction monolithic stack

High-efficiency 1.0 eV GaInAs cells for ultimate integration into AlGaAs/GaAs/GaInAs 3-junction, 2-terminal monolithic devices are described. An n/p 1.0 eV GaInAs cell has been fabricated with a 4.7% (5.4%) solar conversion efficiency under 1-sun, 25 degrees C, AM0 (AM1.5 G) conditions underneath a simulated GaAs cell. While this GaInAs cell had a AM0 J/sub sc/ of 14.6 mA/cm/sup 2/, at least 16 mA/cm/sup 2/ is needed to current match the AlGaAs and GaAs upper cells. A recent n-i-p 1.0 eV GaInAs cell achieved a J/sub sc/ of 16.0 mA/cm/sup 2/. Progress toward monolithic integration with the AlGaAs/GaAs upper cells is described.<
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