GaNPAs solar cells lattice-matched to GaP

III-V semiconductors grown on silicon substrates are very attractive for lower-cost, high-efficiency multijunction solar cells, but lattice-mismatched alloys that result in high dislocation densities have been unable to achieve satisfactory performance. GaN_xP_1-x-yAs_y is a direct-gap III-V alloy that can be grown lattice-matched to Si when y = 4.7x - 0.1. We propose the use of lattice-matched GaNPAs on silicon for high-efficiency multijunction solar cells. We have grown GaN_xP_1-x-yAs_y on GaP (with a similar lattice constant to silicon) by metalorganic chemical vapor phase epitaxy with direct bandgaps in the range of 1.5 to 2.0 eV. We demonstrate the performance of single-junction GaN_xP_1-x-yAs_y solar cells grown on GaP substrates and discuss the prospects for the development of monolithic high-efficiency multijunction solar cells based on silicon substrates.