High efficiency GaAs solar cells using GaInP/sub 2/ window layers

GaAs single-junction solar cells using Ga/sub 0.5/In/sub 0.5/P and having 1 sun, an air mass (AM) of 1.5, and global efficiencies of 25.0-25.7% are reported. The open-circuit voltage (V/sub oc/), short-circuit current (J/sub sc/), and fill factor (ff) for the 25.7% efficient cell were 1.039 V, 28.5 mA/cm/sup 2/, and 86.8%, respectively. The devices were grown at 700 degrees C using conventional atmospheric pressure metalorganic chemical vapor deposition (MOCVD). The antireflection coating is a double layer of MgF/sub 2/ and ZnS. V/sub oc/'s as high as 1.055 V were obtained for some of the devices. This high V/sub oc/ is attributed to the low interface recombination velocity of the Ga/sub 0.5/In/sub 0.5/P-GaAs heterointerface. Factors that affect the efficiency of this device, including the thickness and composition of the Ga/sub 0.5/In/sub 0.5/P window layer, are presented and discussed.<
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