Electrically modulatable photodiode, comprising a substrate having a first and a second p-n junction, a common contact for jointly contacting the p or n dopings of the two p-n junctions, and two further contacts for separately contacting the other doping of the p and n dopings of the two p-n junctions, and a circuit, wherein the circuit is designed to measure a current flow caused by charge carriers which have been generated by impinging radiomagnetic waves in the substrate and which have reached the first further contact, and to switch the second further contact at different times to at least one first and one second switching state, wherein in the first switching state the second further contact is switched to the floating state and in the second switching state a potential is applied, and wherein a blocking voltage applied between the common contact and the first further contact is constant.

Electrically modulatable photodiode, comprising a substrate having a first and a second p-n junction, a common contact for jointly contacting the p or n dopings of the two p-n junctions, and two further contacts for separately contacting the other doping of the p and n dopings of the two p-n junctions, and a circuit, wherein the circuit is designed to measure a current flow caused by charge carriers which have been generated by impinging radiomagnetic waves in the substrate and which have reached the first further contact, and to switch the second further contact at different times to at least one first and one second switching state, wherein in the first switching state the second further contact is switched to the floating state and in the second switching state a potential is applied, and wherein a blocking voltage applied between the common contact and the first further contact is constant.

Disclosed are phototransistors, and more specifically a detector that includes two or more phototransistors, conductively isolated from each other. Embodiments also relate to methods of making the detector.

In accordance with various embodiments of the disclosed subject matter, a phototransistor comprises an NPN or PNP phototransistor having a base including a Si-region, a Ge-region, and a Ge—Si interface region wherein photons are absorbed in the Ge region and conduction-band electrons are attracted to the interface region such that the electrons' mobility is enhanced thereby.

An optical modulator includes an emitter layer with N-type doping having a first bandgap energy; a base layer with P-type doping having a second bandgap energy; a sub-emitter layer disposed between the emitter layer and the base layer, wherein the sub-emitter layer has a third bandgap energy that is less than both the first bandgap energy and the second bandgap energy. The sub-emitter layer provides a barrier to electrons flowing from the emitter layer, while allowing photo-generated holes to recombine in the sub-emitter layer thereby mitigating current amplification.

Mercury cadmium telluride (MCT) dual band photodiode elements are described that include an n-type barrier region interposed between first and second p-type regions. The first p-type region is arranged to absorb different IR wavelengths to the second p-type region in order that the photodiode element can sense two IR bands. A portion of the second p-type region is type converted using ion-beam milling to produce a n-type region that interfaces with the second p-type region and the n-type barrier region.

Mercury cadmium telluride (MCT) dual band photodiode elements are described that include an n-type barrier region interposed between first and second p-type regions. The first p-type region is arranged to absorb different IR wavelengths to the second p-type region in order that the photodiode element can sense two IR bands. A portion of the second p-type region is type converted using ion-beam milling to produce a n-type region that interfaces with the second p-type region and the n-type barrier region.

A double photodiode electromagnetic radiation sensor device including a substrate, a first integrated photodiode (PD1), a second integrated photodiode (PD2), and more than one metal contact. The substrate may be within a first semiconductor material that defines a first face and a second face. The PD1 may include a first doped region extending to the second face and a “n-” type doping. The PD1 may further include a second doped region extending to the second face having a “p+” type doping. The PD2 may include the first doped region, and a layer in a second semiconductor material placed on the second face in contact with the first doped region defining a third face. The PD2 may yet further include a doped layer in the second semiconductor material having a “p+” type doping and overlapping the third face.

A double photodiode electromagnetic radiation sensor device including a substrate, a first integrated photodiode (PD1), a second integrated photodiode (PD2), and more than one metal contact. The substrate may be within a first semiconductor material that defines a first face and a second face. The PD1 may include a first doped region extending to the second face and a “n-” type doping. The PD1 may further include a second doped region extending to the second face having a “p+” type doping. The PD2 may include the first doped region, and a layer in a second semiconductor material placed on the second face in contact with the first doped region defining a third face. The PD2 may yet further include a doped layer in the second semiconductor material having a “p+” type doping and overlapping the third face.

A semiconductor light-receiving element, includes: a semiconductor substrate; a high-concentration layer of a first conductivity type formed on the semiconductor substrate; a low-concentration layer of the first conductivity type formed on the high-concentration layer of the first conductivity type and in contact with the high-concentration layer of the first conductivity type; a low-concentration layer of a second conductivity type configured to form a PN junction interface together with the low-concentration layer of the first conductivity type; and a high-concentration layer of the second conductivity type formed on the low-concentration layer of the second conductivity type and in contact with the low-concentration layer of the second conductivity type. The low-concentration layers have a carrier concentration of less than 1×10.sup.16/cm.sup.3. The high-concentration layers have a carrier concentration of 1×10.sup.17/cm.sup.3 or more. At least one of the low-concentration layers includes an absorption layer with a band gap that absorbs incident light.