Abstract: A semiconductor device has a layered structure. The semiconductor device includes a metallic layer of thickness 1-100 nm, with a thickness optimized to absorb light in a wavelength range of operation. The device further includes an adjacent semiconductor layer additionally adjacent to an ohmic electrical contact, wherein the interface between the metallic layer and the semiconductor layer is electrically rectifying and energy selective. The device further includes a reflective back surface positioned opposite to the semiconductor layer relative to incident light providing broadband reflection in the wavelength range of operation. The semiconductor layer includes a quantum well adjacent to the metallic layer, wherein the energy selectivity is provided by the quantum well allowing charge carrier tunneling from the metallic layer.