Abstract: A magnetic sensor is formed by a diode that includes a silicon element whose bulk is of high resistivity and low recombination velocity material and which includes spaced apart on its top surface n-type and p-type zones to which are provided electrical terminals. The element is treated to form at the top surface regions of high recombination velocity so located that when a voltage is applied between the electrical terminals to establish a flow of minority charge carriers between the p-type and n-type zones, such flow, in the absence of an applied magnetic field to be sensed, is little affected by the surface regions of high recombination velocity, but in the presence of any such field, is deflected into such surface regions and extinguished. Advantagously, the surface regions are formed by etching to form grooves and then ion implanting the grooved regions.

Abstract: In one embodiment a hot electron transistor uses lead telluride as the host crystal. The desired layers of increased band gap to provide the needed heterojunctions at the emitting and collecting junctions are realized either by substitution of europium and selenium in the host crystal or by superlattices of PbTe-CdTe. Variations described use either a tunneling barrier, graded barrier or camel diode barrier are used at the emitting junction. Other embodiments use a bismuth-antimony semiconductor alloy for one or more of the layers of the crystal.

Abstract: A magnetic sensor is formed by a diode that includes a silicon element whose bulk is of high resistivity and low recombination velocity material and which includes spaced apart on its top surface n-type and p-type zones to which are provided electrical terminals. The element is treated to form at the top surface regions of high recombination velocity so located that when a voltage is applied between the electrical terminals to establish a flow of minority charge carriers between the p-type and n-type zones, such flow, in the absence of an applied magnetic field to be sensed, is little affected by the surface regions of high recombination velocity, but in the presence of any such field, is deflected into such surface regions and extinguished. Advantageously, the surface regions are formed by etching to form grooves and then ion implanting the grooved regions.

Abstract: A double heterojunction lead salt semiconductor diode laser having an optical cavity of PbEuSeTe alloy with a quantum well having reduced Eu concentration disposed to one side of the optical cavity, the optical cavity having a given lattice constant and index of refraction. The optical cavity is sandwiched between two PbEuSeTe alloy confinement layers that are mutually of opposite conductivity type and have substantially the same lattice constant as the optical cavity. A pn junction surface in the optical cavity and preferably on or adjacent the quantum well layer injects charge carriers into the optical cavity. The larger energy band gap between the quantum well layer and its adjacent sandwiching confinement layer strongly confines charge carriers of one type from recombining in the oppositely doped adjacent sandwiching layer. This results in a decreased threshold current (I.sub.th) and a higher maximum operating temperature.

Abstract: A double heterojunction lead salt infrared diode laser having an active region layer of a lead salt semiconductor of a given lattice constant, energy band gap, and index of refraction. The active region layer is sandwiched between two lead salt semiconductor layers containing strontium and selenium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active region layer. In addition, the two outside layers have an energy band gap greater than the active region layer and an index of refraction less than the active region layer. The resulting laser has lattice matching, as well as enhanced carrier confinement and optical confinement.

Abstract: Spectroscopic measurements of stable isotopes are performed using a tunable lead salt diode laser. The design of the system is based upon the optimization of isotopic spectral lines from two different path lengths in an absorption cell using a single gaseous sample. A short path cell to measure the more abundant species and a long path cell to measure the less abundant species are used. A micrometer adjustment of a path length is used for equalizing spectral line intensities to obtain a measure of isotope enrichment or of absolute isotopic concentration.

Abstract: A double heterojunction lead salt infrared diode laser having an active region layer of a lead salt semiconductor of a given lattice constant, energy band gap, and index of refraction. The active region layer is sandwiched between two lead salt semiconductor layers containing calcium and one element selected from the group consisting of europium and strontium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active region layer. In addition, the two outside layers have an energy band gap greater than the active region layer and an index of refraction less than the active region layer. The resulting laser has lattice matching, as well as enhanced carrier confinement and optical confinement.

Abstract: A double heterojunction lead salt diode infrared laser having an active region layer of a lead salt semiconductor of a given lattice constant, energy band gap, and index of refraction. The active region layer is sandwiched between two lead salt semiconductor layers containing europium and selenium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active region layer. In addition, the europium and selenium-containing lead chalcogenide layers have an energy band gap greater than the active region layer and an index of refraction less than the active region layer. Hence, the laser has lattice matching, as well as enhanced carrier confinement and optical confinement.

Abstract: A double heterojunction lead salt diode infrared laser having an active region of a lead salt semiconductor of a given lattice constant, energy band gap, and index of refraction. The active region is sandwiched between two lead salt semiconductor layers containing ytterbium that are mutually of opposite conductivity type and have substantially the same lattice constant as the active layer. In addition, the ytterbium-containing lead salt layers have an energy band gap greater than the active layer and an index of refraction less than the active layer. Hence, the laser has lattice matching, as well as enhanced, carrier confinement and optical confinement.