Solar cells with a rear potential barrier based on isotypic heterojunctions in the system GaAs-AlAs

The conversion efficiency of solar cells with an isotypic rear heterojunction based on a structure with p-conductivity in the base region is investigated experimentally using solar cells fabricated by growing epitaxial layers of GaAs and Al(x)Ga(1-x)As on a pGaAs substrate oriented in the /100/ plane. The effect of the isotypic heterojunction on carrier collection processes is found to be more pronounced at small distances from the boundary of the p-n transition space charge region. Spectral dependences of quantum efficiency are presented for three solar cells with base regions 1.4, 2.1, and 3.2 microns thick. It is shown that solar cells with a rear potential barrier are more efficient than ordinary solar cells in the case of concentrated solar radiation.