Abstract: An AlSb lattice matched barrier infrared detector architecture with the AlSb binary barrier layer enables implementation of strain layer superlattice absorbers with higher absorption coefficients for improved quantum efficiency, presents a simplified structure for epitaxial growth, and enables the utilization of bulk InAs0.815Sb0.185 absorber material with a 5.0 ?m cutoff for both single and dual color devices. Such an infrared detector is formed by growing the detector material; bottom contact, 1st absorber layer, AlSb barrier, optional graded layer, 2nd absorber layer, top contact, on top of an AlSb lattice matched buffer layer. Epitaxial growth on the AlSb lattice enables the deposition of unstrained bulk InAs0.815Sb0.185 with a 5.0 ?m cutoff, as well as InAs/InAs(x)Sb(1-x) superlattice absorbers with a continuously tunable cutoff from mid-wavelength to long-wavelength infrared.

Abstract: An infrared detector having a hole barrier region adjacent to one side of an absorber region, an electron barrier region adjacent to the other side of the absorber region, and a semiconductor adjacent to the electron barrier.

Abstract: A multi-waveband temperature sensor array, in which each superpixel (e.g., 2×2 pixel cell) operates at a distinct thermal infrared (IR) waveband (e.g. four wavebands) is disclosed. Using an example high spatial resolution, four-band thermal IR band photodetector array, accurate temperature measurements on the surface of an object can be made without prior knowledge of the object emissivity. The multiband photodetector may employ intersubband transition in III-V semiconductor-based quantum layered structures where each photodetector stack absorbs photons within the specified wavelength band while allowing the transmission of photons in other spectral bands, thus efficiently permitting multiband detection. This produces multiple, spectrally resolved images of a scene that are recorded simultaneously in a single snapshot of the FPA. From the multispectral images and calibration information about the system, computational algorithms are used to produce the surface temperature map of a target.

Abstract: A quantum well infrared photodetector (QWIP) focal plane array having structures, each structure having stacked layers of quantum wells and a reflective grating to provide polarization sensitivity. The reflective grating is etched to provide electrical contacts for individual pixels. The reflective gratings comprise grooves, where the grooves for a particular structure run in a particular direction to provide polarization sensitivity. Each structure may comprise groups of quantum well layers, each group sensitive to a particular frequency band. By shorting out unwanted quantum well layers, and by forming the reflective gratings to come into contact with the quantum well layers having a particular frequency band sensitivity, the pixels in the QWIP focal plane array may provide frequency and polarization information.

Abstract: An nBn detector is described where for some embodiments the barrier layer has a concentration gradient, for some embodiments the absorption layer has a concentration gradient, and for some embodiments the absorption layer is a chirped strained layer super lattice. The use of a graded barrier or absorption layer, or the use of a chirped strained layer super lattice for the absorption layer, allows for design of the energy bands so that the valence band may be aligned across the device. Other embodiments are described and claimed.

Abstract: A barrier infrared detector with absorber materials having selectable cutoff wavelengths and its method of manufacture is described. A GaInAsSb absorber layer may be grown on a GaSb substrate layer formed by mixing GaSb and InAsSb by an absorber mixing ratio. A GaAlAsSb barrier layer may then be grown on the barrier layer formed by mixing GaSb and AlSbAs by a barrier mixing ratio. The absorber mixing ratio may be selected to adjust a band gap of the absorber layer and thereby determine a cutoff wavelength for the barrier infrared detector. The absorber mixing ratio may vary along an absorber layer growth direction. Various contact layer architectures may be used. In addition, a top contact layer may be isolated into an array of elements electrically isolated as individual functional detectors that may be used in a detector array, imaging array, or focal plane array.

Abstract: An infrared detector having a hole barrier region adjacent to one side of an absorber region, an electron barrier region adjacent to the other side of the absorber region, and a semiconductor adjacent to the electron barrier.

Abstract: The present invention is directed to methods of photonic crystal formation, and to methods and apparatus for using such photonic crystals, particularly in conjunction with detector arrays. Photonic crystal parameters and detector array parameters are compared to optimize the selection and orientation of a photonic crystal shape. A photonic crystal is operatively positioned relative to a plurality of light sensors. The light sensors can be separated by a pitch distance and positioned within one half of the pitch distance of an exit surface of the photonic crystals.

Abstract: An nBn detector is described where for some embodiments the barrier layer has a concentration gradient, for some embodiments the absorption layer has a concentration gradient, and for some embodiments the absorption layer is a chirped strained layer super lattice. The use of a graded barrier or absorption layer, or the use of a chirped strained layer super lattice for the absorption layer, allows for design of the energy bands so that the valence band may be aligned across the device. Other embodiments are described and claimed.

Abstract: Quantum-well sensors having an array of spatially separated quantum-well columns formed on a substrate. A grating can be formed increase the coupling efficiency.

Abstract: Devices and techniques for coupling radiation to intraband quantum-well semiconductor sensors that are insensitive to the wavelength of the coupled radiation. At least one reflective surface is implemented in the quantum-well region to direct incident radiation towards the quantum-well layers.

Abstract: A quantum well infrared photodetector (QWIP) that provides two-color image sensing. Two different quantum wells are configured to absorb two different wavelengths. The QWIPs are arrayed in a focal plane array (FPA). The two-color QWIPs are selected for readout by selective electrical contact with the two different QWIPs or by the use of two different wavelength sensitive gratings.

Abstract: A quantum well can be designed to detect light of a particular wavelength by tailoring the potential depth and width of the well. The design produces two energy states in the well separated by the desired photon energy. The GaAs/AlxGa1-xAs material system allows the quantum well shape to be varied over a range wide enough to enable light detection at wavelengths longer than approximately 6 ?m. Hence, large bandgap materials such as GaAs/AlxGa1-xAs material has made fabrication of a large focal plane arrays tuned to detect light at wavelengths from 6 to 25 ?m possible.

Abstract: Device designs and techniques for reducing the dark current in quantum-well detectors.

Abstract: A quantum well infrared photodetector (QWIP) that provides two-color image sensing. Two different quantum wells are configured to absorb two different wavelengths. The QWIPs are arrayed in a focal plane array (FPA). The two-color QWIPs are selected for readout by selective electrical contact with the two different QWIPs or by the use of two different wavelength sensitive gratings.

Abstract: Devices and techniques for coupling radiation to intraband quantum-well semiconductor sensors that are insensitive to the wavelength of the coupled radiation. At least one reflective surface is implemented in the quantum-well region to direct incident radiation towards the quantum-well layers.

Abstract: Device designs and techniques for forming multiple-band quantum-well detectors.

Abstract: Devices and techniques for coupling radiation to intraband quantum-well semiconductor sensors that are insensitive to the wavelength of the coupled radiation. At least one reflective surface is implemented in the quantum-well region to direct incident radiation towards the quantum-well layers.

Abstract: A three-color QWIP focal plane array is based on a GaAs/AlGaAs material system. Three-color QWIPs enable target recognition and discriminating systems to precisely obtain the temperature of two objects in the presence of a third unknown parameter. The QWIPs are designed to reduce the normal reflection over a significant wavelength range. One aspect of the present invention involves two photon absorptions per transition in a double quantum well structure which is different from typical QWIP structures. This design is expected to significantly reduce the dark current as a result of higher thermionic barriers and therefore allow the devices to operate at elevated temperatures. The device is expected to be fabricate using a GaAs/AlxGa1−xAs material system on a semi-insulating GaAs substrate by Molecular Beam Epitacy (MBE).

Abstract: Device designs and techniques for forming multiple-band quantum-well detectors.