Siemens Aktiengesellschaft

Wolfgang Ruhle

Claus Weyrich

Peter Glasow

A temperature sensor having a semiconductor body is disclosed. The semiconductor body includes a substrate of a compound semiconductor and an epitaxial layer of a mixed crystal in which different conduction band minima with different effective masses are energy-wise closely adjacent. A particular embodiment comprises the mixed crystal series gallium-aluminum-arsenic having the composition Ga.sub.1-x Al.sub.x As, in which the aluminum concentration is 0.2.ltoreq.x.ltoreq.0.43. The temperature sensor formed in this manner provides a simplified design and a wide linear temperature range. Additionally, the temperature range is extended without the need for a shunt resistance.

Temperature sensor

A detector system for computer tomography or computer radiography contains a plurality of flat detectors which are arranged side by side in the plane of a fan-shaped beam of ionizing rays. According to the invention, detectors of high purity germanium are provided, whose volume is selected so that the contribution of the generation-recombination current to the shot noise of the detectors is substantially smaller than customary in detectors for ionizing rays. With these detectors one obtains a good local resolution as well as a good signal-to-noise ratio and one requires no vacuum and no cooling.

Detector apparatus and method for computer tomography and radiography

A light-emitting diode comprises III-V semiconductor material having a pn junction as its light-active zone from which luminescent radiation is emitted, the radiation having a pressure-dependent characteristic. The diode is characterized in that, for the purpose of pressure-dependent brightness of the light radiation, the composition of the light-active zone at the pn junction comprises a semiconductor material which has a composition which corresponds to a position close to the transition from a direct energy gap to an indirect energy gap and at which a change of the composition would result in a significant change in the brightness of the emission. The invention is particularly useful for potential-free measurement of pressure forces.

Light-emitting diode suitable as a pressure sensor

A pressure sensor having a semiconductor body is disclosed. The sensor comprises a substrate of a compound semiconductor and an epitaxial layer of a mixed crystal, in which different conduction band minima with different effective masses are closely adjacent energywise, particularly from the mixed crystal series gallium-aluminum-arsenic with the composition Ga.sub.1-x Al.sub.x As, in which the aluminum concentration is 0.19.ltoreq.x.ltoreq.0.43. The sensor described has a simplified design and predetermined pressure ranges can be set by varying the concentration of the crystal constituents.

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Erlangen, Germany

Wolfgang Ruhle