An infrared detector and a method for forming it are provided. The detector includes absorber, barrier, and contact regions. The absorber region includes a first semiconductor material, with a first lattice constant, that produces charge carriers in response to infrared light. The barrier region is disposed on the absorber region and comprises a superlatice that includes (i) first barrier region layers comprising the first semiconductor material, and (ii) second barrier region layers comprising a second semiconductor material, different from, but lattice matched to, the first semiconductor material. The first and second barrier region layers are alternatingly arranged. The contact region is disposed on the barrier region and comprises a superlattice that includes (i) first contact region layers comprising the first semiconductor material, and (ii) second contact region layers comprising the second semiconductor material layer. The first and second contact region layers are alternatingly arranged.

An electromagnetic radiation detector includes an InP substrate having a first surface opposite a second surface; a first InGaAs electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths; a set of one or more buffer layers stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the first set of electromagnetic radiation wavelengths; a second InGaAs electromagnetic radiation absorber stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths; and an immersion condenser lens formed on the second surface and configured to direct electromagnetic radiation through the InP substrate and toward the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber.

A method of fabricating multijunction solar cell including an upper solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a lower solar subcell disposed below the upper solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the upper and lower solar subcells and having a graded lattice constant that matches the upper first subcell on a first side and the second solar subcell on the second side opposite the first side, and having a fifth band gap that is greater than the second band gap of the upper solar subcell.

Processes and devices for continuous compositional grading in photodetectors and electro-absorption modulators (EAM) are provided. An example photodetector includes a multi-layered structure comprising a collector region, an absorber region, a grading layer, and a peripheral layer, all aligned along a detection axis. The grading layer, positioned adjacent to the absorber region, includes multiple sub-layers that define a continuous compositional grading to facilitate smooth carrier transport and reduce recombination. Similarly, an example electro-absorption modulator (EAM) device includes a waveguide mesa formed on a semiconductor substrate, comprising a multi-quantum well (MQW) core layer, upper and lower near-core cladding layers, and upper and lower central cladding layers. The EAM device features both upper and lower grading layers, each positioned between the near-core cladding layers and the adjacent central cladding layers. These grading layers include multiple sub-layers that define a continuous compositional grading, facilitating smooth transitions between the MQW core and surrounding cladding layers.

In one aspect, an avalanche photodiode, includes an absorber, a first superlattice structure directly connected to the absorber and configured to multiply holes and a second superlattice structure directly connected to the first superlattice structure and configured to multiply electrons. The first and second superlattice structures include III-V semiconductor material. The avalanche photodiode is a dual mode device configured to operate in either a linear mode or a Geiger mode. In another aspect, a method includes fabricating the avalanche diode.

A sensor includes an InGaAs photodetector configured to convert received infrared radiation into electrical signals. A notch filter is operatively connected to the InGaAs photodetector to block detection of wavelengths within at least one predetermined band. An imaging camera system includes an InGaAs photodetector configured to convert received infrared radiation into electrical signals, the InGaAs photodetector including an array of photodetector pixels each configured to convert infrared radiation into electrical signals for imaging. At least one optical element is optically coupled to the InGaAs photodetector to focus an image on the array. A notch filter is operatively connected to the InGaAs photodetector to block detection of wavelengths within at least one predetermined band. A ROIC is operatively connected to the array to condition electrical signals from the array for imaging.

Techniques are disclosed for providing the weapon-mounted optical scope that provides for wind sensing and the display a ballistic solution without the need for a separate device. Embodiments may include various additional sensors housed within the weapon-mounted optical scope to provide data for the ballistic solution calculation. Embodiments may further include a display at the input aperture rather than internally at the first-focal-plane, enabling for simpler, more cost effective embodiments. Additionally or alternatively, embodiments may include a laser, separate from the wind sensing laser, to perform range-finding functions, and/or an enhanced-image assembly.

Embodiments of the invention generally relate to photovoltaic devices. In one embodiment, a method for forming a gallium arsenide based photovoltaic device includes providing a semiconductor structure, the structure including an absorber layer comprising gallium arsenide. A bypass function is provided in a p-n junction of the semiconductor structure, where under reverse-bias conditions the p-n junction breaks down in a controlled manner by a Zener breakdown effect.

Certain embodiments of the present invention may be directed to a transistor structure. The transistor structure may include a semiconductor substrate. The semiconductor substrate may include a drift region, a collector region, an emitter region, and a lightly-doped/undoped region. The lightly-doped/undoped region may be lightly-doped and/or undoped. The transistor structure may also include a heterostructure. The heterostructure forms a heterojunction with the lightly-doped/undoped region. The transistor structure may also include a collector terminal. The collector terminal is in contact with the collector region. The transistor structure may also include a gate terminal. The gate terminal is in contact with the heterostructure. The transistor structure may also include an emitter terminal. The emitter terminal is in contact with the lightly-doped/undoped region and the emitter region.

A method for fabricating an optically transparent conductor including depositing a plurality of metal nanowires on a substrate, annealing or illuminating the plurality of metal nanowires to thermally or optically fuse nanowire junctions between metal nanowires to form a metal nanowire network, disposing a graphene layer over the metal nanowire network to form a nanohybrid layer comprising the graphene layer and the metal nanowire network, depositing a dielectric passivation layer over the nanohybrid layer, patterning the dielectric passivation layer using lithography, printing, or any other method of patterning to define an area for the optically transparent conductor, and etching the patterned dielectric passivation layer to define the optically transparent conductor.