GaAs Shallow-homojunction solar cells on Ge-coated Si substrates

Solar cells with conversion efficiencies of 12% (AM1) have been fabricated from single-crystal GaAs epilayers grown by CVD on Ge-coated Si substrates. The cells utilize an n+/p/p+shallow-homo junction GaAs structure on a thin (<0.2 µm) epitaxial Ge layer. These solar cells are the first reported GaAs devices fabricated on Si substrates.