Patent ID: 7309832

Claim:
A multi-junction, monolithic solar cell device for converting solar radiation into electrical energy, the multi-junction solar cell device comprising: a bottom active cell having a single-crystal silicon substrate base and a bottom emitter layer, which together farm a first p-n junction; a top active cell having a top base layer and a top emitter layer which together form a second p-n junction, and wherein the top active cell includes at least one III-V semiconductor layer that includes at least one of (GaN 0.02 P 0.98 ) 1-n (GaN 0.19 As 0.81 ) n , (Ga N 0.02 P 0.98 ) 1-n (InN 0.47 P 0.53 ) n , and (B 0.25 Ga 0.75 As) 1-n (B 0.02 Ga 0.98 P) n , where 0<n<1, and that is lattice-matched to the silicon substrate base; and a tunnel junction layer interposed between the bottom active cell and the top active cell for facilitating electrical current flow between the bottom active cell and the top active cell.