Patent ID: 8912432

Claim:
A photovoltaic device, comprising: a n-doped GaAs layer; a p + -doped AlGaAs layer wherein recesses are formed in the p + -doped AlGaAs layer; a n-doped AlGaAs intermediate layer interposed between the n-doped GaAs layer and the p + -doped AlGaAs layer, wherein the n-doped intermediate AlGaAs layer and the p + -doped AlGaAs layer form a p-n junction such that electric energy is created when photons are absorbed by the p-n junction, and wherein the n-doped AlGaAs intermediate layer provides a transition between the n-doped GaAs layer and the p + -doped AlGaAs layer; and an interface layer comprising a Group III-V compound semiconductor above and indirect contact with the p + -doped AlGaAs layer, wherein a length in the horizontal direction of the p + -doped AlGaAs layer is longer than a length in the horizontal direction of the interface layer.