A multijunction solar cell including interconnected first and second discrete semiconductor regions disposed adjacent and parallel to each other including first top solar subcell, second (and possibly third) lattice matched middle solar subcells; a graded interlayer adjacent to the last middle solar subcell; and a bottom solar subcell adjacent to said graded interlayer being lattice mismatched with respect to the last middle solar subcell; wherein an opening is provided from the bottom side of the semiconductor body to one or more of the solar subcells so as to allow a discrete electrical connector to be made extending in free space and to electrically connect contact pads on one or more of the solar subcells.

High speed, and high timing resolution photon detecting systems and methods are presented with multiplication and self-quenching and self-recovering functions.

A photovoltaic cell includes a semiconductor element (20) formed from a direct semiconductor and a transparent biasing agent (28) overlying a first portion of the front face (22) of the semiconductor, the biasing agent producing a first depletion region (30) in the semiconductor element. A collector (40) directly contacts a second portion of the front face. The collector produces a second depletion region (44) in the semiconductor element. The collector (40) is out of direct conductive contact with the biasing agent (28) but in proximity to the biasing agent. A continuous region at least partially depleted of majority carriers extends between the first and second depletion regions at the front face of the semiconductor element, The continuous region may include overlapping portions of the first and second depletion regions (30,44), or may include an additional depletion region (160) formed by a charged dielectric (147).

An ICIP comprises: a number N.sub.s of IC stages, wherein N.sub.s is configured to achieve a fundamental limit of the detectivity D.sub.peak* the ICIP within a range, and wherein each of the IC stages comprises: a hole barrier; an absorber coupled to the hole barrier and comprising a thickness d, wherein d is configured to achieve D.sub.peak* within the range; and an electron barrier coupled to the absorber. A method of manufacturing an ICIP comprises: determining a number N.sub.s of IC stages of the ICIP, wherein N.sub.s is configured to achieve a peak detectivity D.sub.peak* of the ICIP within a range; determining a thickness d of an absorber, wherein d is configured to achieve D.sub.peak* within the range; obtaining a substrate; forming an electron barrier on the substrate, the absorber having d on the electron barrier, and a hole barrier on the absorber; and repeating the forming N.sub.s times.

A monolithic multi-junction solar cell comprising a first III-V subcell and a second III-V subcell and a third III-V subcell and a fourth Ge subcell, wherein the subcells are stacked on top of one another in the specified order, and the first subcell forms the top subcell and a metamorphic buffer is formed between the third subcell and the fourth subcell and all subcells each have an n-doped emitter layer and a p-doped base layer and the emitter doping in the second subcell is lower than the base doping.

A photo detector having a substrate and a first structure formed on the substrate. The first structure includes an emitter layer formed on the substrate and a base layer formed on the emitter layer. Further, the first structure includes a collector layer formed on the base layer. The collector layer has a plasmonic structure. The plasmonic structure includes a first plurality of mesa structures. Each of the mesa structures of the first plurality of mesa structures includes a second plurality of mesa structures having ridges arranged in a regularly repeating pattern.

A method includes forming an assembly of layers including an InP cap layer on an InGaAs absorption region layer, wherein the InGaAs layer is on an n-InP layer, and wherein an underlying substrate layer underlies the n-InP layer. The method includes removing a portion of the InP cap and n-InP layer by dry etching.

A photodetection element that includes: a substrate with a high infrared transmittance in a desired wavelength region; an electron barrier layer of a type-I superlattice structure, the electron barrier layer being formed above the substrate and lattice-matched to the substrate; and a light-receiving layer of a type-II superlattice structure, formed in contact with the electron barrier layer.

A device for producing electricity. The device includes a substrate having spaced apart first and second surfaces and doped a first dopant type, first semiconductor material layers disposed atop the first substrate surface and doped the first dopant type, and second semiconductor material layers disposed atop the first semiconductor material layers and doped a second dopant type. A first contact is in electrical contact with the second substrate surface or in electrical contact with one of the first semiconductor material layers. A beta particle source emits beta particles that penetrate into the semiconductor material layers; the beta particle source is proximate the uppermost layer of the second plurality of semiconductor material layers. A second contact is in electrical contact with one of the second plurality of semiconductor material layers. In one embodiment, bi-polar contacts (the first and second contacts) are co-located on each major face of the device.

A dynamic concentrator system having a concentrator lens, a tracker platform and a receiver. In an embodiment, the concentrator lens is configured to receive an incoming light at an entrance angle a and concentrate the light beam on a focus spot. The tracker platform has a detector optical aperture and one or more actuators. The detector optical aperture can be configured to receive the concentrated light beam. The actuators can move the detector optical aperture in a spatial plane to a location of the focus spot. The receiver has a detector optically coupled to the detector optical aperture to receive the concentrated light beam from the detector optical aperture.