Radiation effects of two-terminal, monolithic InP/Ga/sub 0.47/In/sub 0.53/As tandem solar cells

Two-terminal, monolithic InP/Ga/sub 0.47/In/sub 0.53/As tandem solar cells grown by the atmospheric-pressure metalorganic vapor phase epitaxy (APMOVPE) technique have been studied under successive fluences of 1 MeV electrons. Illuminated I-V results obtained at 1 sun, AM0 (25/spl deg/C) are described. Besides the high performance of these novel devices under particle irradiation, the current mismatch between the top and bottom subcells began to be noticeable at a fluence of 3/spl times/10/sup 15/ cm compared to 3/spl times/10/sup 14/ cm/sup -2/ as demonstrated in previous cells. This is a dramatic improvement in the radiation resistance. The cells exhibited beginning-of-life (BOL) efficiencies as high as 22%, and it is suggested that additional slight improvement in the radiation tolerance of the tandem cells can be achieved by further adjusting the device structure.<>