| abstract |
A high-efficiency four-junction solar cell includes: an InP growth substrate; a first subcell formed over the growth substrate, with a first band gap, and a lattice constant matched with that of the growth substrate; a second subcell formed over the first subcell, with a second band gap larger than the first band gap, and a lattice constant matched with that of the growth substrate; a third subcell formed over the second subcell, with a third band gap larger than the second band gap, and a lattice constant matched with that of the substrate lattice; a composition gradient layer formed over the third subcell, with a fourth band gap larger than the third band gap; and a fourth subcell formed over the composition gradient layer, with a fifth band gap larger than the third band gap, and a lattice constant mismatched with that of the substrate. |