Investigation of complementary p-n-p and n-p-n solar cell stages

Theoretical and experimental test results are reported for solar cell stages with complementary p--n--p and n--p--n heterostructures. Calculations reveal that efficiencies of 40--45% are attainable in such photocells. The parameters of the heterostructures corresponding to equal currents in the different stages are calculated, so that complementary pairs of photocells can be combined in a battery. GaAs--AlAs heterostructures were used to fabricate p--n--p and n--p--n solar cell stages, and the calculated parameters have been confirmed by test results.