A dual-band infrared detector is provided. The dual-band infrared detector includes a first absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the first absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic. The dual-band infrared detector also includes a second absorption layer coupled to the barrier layer opposite the first absorption layer. The second absorption layer is sensitive to radiation in only a medium wavelength infrared spectral band. The composition of the alloy used to fabricate the barrier layer is selected such that valence bands of the barrier layer and the first and second absorption layers substantially align.

An infrared detector is provided. The infrared detector includes an absorption layer sensitive to radiation in only a short wavelength infrared spectral band, and a barrier layer coupled to the absorption layer. The barrier layer is fabricated from an alloy including aluminum and antimony, and at least one of gallium or arsenic, and the composition of the alloy is selected such that valence bands of the absorption layer and the barrier layer substantially align.

A method of manufacturing a photodiode including a useful layer made of a semi-conductor alloy. The useful layer has a band gap value which decreases from its upper face to its lower face. A step of producing a first doped region forming a PN junction with a second doped region of the useful layer, said production of a first doped region including a first doping step, so as to produce a base portion; and a second doping step, so as to produce at least one protuberance protruding from the base portion and in the direction of the lower face.

An infrared camera system is provided to detect absorption of infrared radiation in a selected spectral bandwidth. In one example, an infrared camera system includes a lens adapted to receive infrared radiation from a survey scene comprising one or more gasses. The infrared camera system also includes a focal plane array comprising a plurality of quantum well infrared photo detectors (QWIPs). The QWIPs are tuned to detect a limited spectral bandwidth of the infrared radiation corresponding to at least a portion of an infrared absorption band of the one or more gasses. The infrared camera system also includes an optical band pass filter positioned substantially between the lens and the focal plane array. The optical band pass filter is adapted to filter the infrared radiation to a wavelength range substantially corresponding to the limited spectral bandwidth of the QWIPs before the infrared radiation is received by the focal plane array.

A photovoltaic cell is provided that can be used under high levels of solar concentration (1000 suns). The present cell includes at least one junction produced on a substrate based on gallium antimonide, the at least one junction having two alloys based on an antimonide material (Ga.sub.1-xAl.sub.xAs.sub.ySb.sub.1-y) lattice-matched on the substrate GaSb. If there are several junctions, two neighbouring junctions are separated by a tunnel junction.

A tunnel junction for a semiconductor device is disclosed. The tunnel junction includes a n-doped tunnel layer and a p-doped tunnel layer. The p-doped tunnel layer is constructed of aluminum gallium arsenide antimonide (AlGaAsSb). A semiconductor device including the tunnel junction with the p-doped tunnel layer constructed of AlGaAsSb is also disclosed.

A light receiving device includes a substrate having a principal surface and a back surface, the substrate containing GaSb semiconductor co-doped with a p-type dopant and an n-type dopant; a stacked semiconductor layer disposed on the principal surface of the substrate, the stacked semiconductor layer including an optical absorption layer; and an incident surface provided on the back surface of the substrate that receives an incident light. The optical absorption layer includes a super-lattice structure including a first semiconductor layer and a second semiconductor layer that are alternately stacked. In addition, the first semiconductor layer contains gallium and antimony as constituent elements. The second semiconductor layer is composed of a material different from a material of the first semiconductor layer.

The present invention is directed to a position sensing detector made of a photodiode having a semi insulating substrate layer; a buffered layer that is formed directly atop the semi-insulating substrate layer, an absorption layer that is formed directly atop the buffered layer substrate layer, a cap layer that is formed directly atop the absorption layer, a plurality of cathode electrodes electrically coupled to the buffered layer or directly to the cap layer, and at least one anode electrode electrically coupled to a p-type region in the cap layer. The position sensing detector has a photo-response non-uniformity of less than 2% and a position detection error of less than 10 m across the active area.

A semiconductor layered structure according to the present invention includes a substrate formed of a III-V compound semiconductor; and semiconductor layers disposed on the substrate and formed of III-V compound semiconductors. The substrate has a majority-carrier-generating impurity concentration of 110.sup.17 cm.sup.3 or more and 210.sup.20 cm.sup.3 or less, and the impurity has an activation ratio of 30% or more.

A method for producing an optical device includes: forming an n-type layer over a substrate by a MOCVD method; forming a first active layer over the n-type layer by a MOCVD method; forming an intermediate layer over the first active layer by a MOCVD method; forming a second active layer having a band gap energy different from the band gap energy of the first active layer over the intermediate layer by a MOCVD method; forming a first p-type layer over the second active layer by a MOCVD method; forming a groove having a depth reaching the intermediate layer from a side of the first p-type layer; forming an electron blocking layer by sputtering over the intermediate layer exposed at a bottom surface of the groove; forming a semiconductor layer over the electron blocking layer by sputtering; and forming a second p-type layer as defined herein.