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.

Abstract: A ballistic carrier spectral sensor includes a photon absorption region to generate photo-generated carriers from incident light; a first potential barrier region adjacent the photon absorption region and having an adjustable height defining a minimum energy of the photo-generated carriers required to pass therethrough; a second potential barrier region having an adjustable height defining a minimum energy of the photo-generated carriers required to pass therethrough; a spillage well region disposed between the first potential barrier region and the second potential barrier region and configured to collect photo-generated carriers having an energy lower than that required to pass through the second potential barrier region; and a collection region adjacent the second potential barrier region and configured to collect carriers that cross the second potential barrier region.

Abstract: A resonant tunneling device includes a first semiconductor material with an energy difference between valence and conduction bands of Eg1, and a second semiconductor material with an energy difference between valence and conduction bands of Eg2, wherein Eg1 and Eg2 are different from one another. The device further includes an energy selectively transmissive interface connecting the first and second semiconductor materials.

Abstract: A non-close-packed vertical junction photovoltaic device includes a substrate, a two-dimensional array of elongate nanostructures extending substantially perpendicularly from a surface of the substrate, and a thin film solar cell disposed over the nanostructures such that the thin film solar cell substantially conforms to the topography of the nanostructures. An average separation of nearest neighbor solar cell coated nanostructures is greater than zero and less than a vacuum wavelength of light corresponding to a band gap of absorption. The thin film solar cell may include an active region that conforms to the elongate nanostructures, a first electrode that conforms to a surface of the active region, and a second electrode. A separation of opposing outer surfaces of the first electrode extending along adjacent elongate nanostructures is greater than zero and less than the vacuum wavelength of the light corresponding to the band gap of the active region.

Abstract: A resonant tunneling device includes a first semiconductor material with an energy difference between valence and conduction bands of Eg1, and a second semiconductor material with an energy difference between valence and conduction bands of Eg2, wherein Eg1 and Eg2 are different from one another. The device further includes an energy selectively transmissive interface connecting the first and second semiconductor materials.

Abstract: A multijunction photovoltaic structure includes a first subcell including a p-n or p-i-n junction with elongated structures; and a second subcell, arranged in tandem with the first subcell, and including a planar p-n or p-i-n junction.