A tandem photovoltaic device includes: an upper cell unit, a lower cell unit and a tunnel junction positioned between the upper cell unit and the lower cell unit; the tunnel junction includes an upper transport layer, a lower transport layer, and an intermediate layer positioned between the upper transport layer and the lower transport layer, the intermediate layer is an ordered defect layer, or, the intermediate layer is a continuous thin layer, or, the intermediate layer includes a first layer in contact with the lower transport layer and a second layer in contact with the upper transport layer; a doping concentration of the first layer is 10-10,000 times of a doping concentration of the lower transport layer, and the doping concentration of the first layer is less than 10.sup.21cm.sup.−3; a doping concentration of the second layer is 10-10,000 times of a doping concentration of the upper transport layer.

An integrated optical sensor includes a photon-detection module of a single-photon avalanche photodiode type. The detection module includes a semiconductive active zone in a substrate. The semiconductive active zone includes a region that contains germanium with a percentage between 3% and 10%. This percentage range is advantageous because it makes it possible to obtain a material firstly containing germanium (which in particular increases the efficiency of the sensor in the infrared or near infrared domain) and secondly having no or very few dislocations (which facilitates the implementation of a functional sensor in integrated form).

A planar photodiode including a main layer including an n-doped first region, a p-doped second region, and an intermediate region, and also a p-doped peripheral lateral portion. It also includes a peripheral intermediate portion, made of an alternation of monocrystalline thin layers of silicon-germanium and germanium, located on the first face, and extending between and at a non-zero distance from the doped first region and from the peripheral lateral portion so as to surround the doped first region in a main plane.

A planar photodiode including a main layer including an n-doped first region, a p-doped second region, and an intermediate region, and also a p-doped peripheral lateral portion. It also includes a peripheral intermediate portion, made of an alternation of monocrystalline thin layers of silicon-germanium and germanium, located on the first face, and extending between and at a non-zero distance from the doped first region and from the peripheral lateral portion so as to surround the doped first region in a main plane.

A semiconductor device includes a normally-on junction FET having a gate electrode, a source electrode and a drain electrode and a normally-off MOSFET having a gate electrode, a source electrode and a drain electrode. The source electrode of the junction FET is electrically connected to the drain electrode of the MOSFET, and the junction FET is thus connected to the MOSFET in series. The gate electrode of the junction FET is electrically connected to the gate electrode of the MOSFET.

A photodetector having a small form factor and having high detection efficiency with respect to both visible light and infrared rays may include a first electrode, a collector layer on the first electrode, a tunnel barrier layer on the collector layer, a graphene layer on the tunnel barrier layer, an emitter layer on the graphene layer, and a second electrode on the emitter layer. The photodetector may be included in an image sensor. An image sensor may include a substrate, an insulating layer on the substrate, and a plurality of photodetectors on the insulating layer. The photodetectors may be aligned with each other in a direction extending parallel or perpendicular to a top surface of the insulating layer. The photodetector may be included in a LiDAR system.

A process for fabricating an optoelectronic device including an array of germanium-based photodiodes including the following steps: producing a stack of semiconductor layers, made from germanium; producing trenches; depositing a passivation intrinsic semiconductor layer, made from silicon; annealing, ensuring, for each photodiode, an interdiffusion of the silicon of the passivation semiconductor layer and of the germanium of a semiconductor portion, thus forming a peripheral zone of the semiconductor portion, made from silicon-germanium.

A semiconductor device for flame detection, including: a semiconductor body having a first conductivity type conductivity, delimited by a front surface and forming a cathode region; an anode region having a second conductivity type conductivity, which extends within the semiconductor body, starting from the front surface, and forms, together with the cathode region, the junction of a photodiode that detect ultraviolet radiation emitted by the flames; a supporting dielectric region; and a sensitive region, which is arranged on the supporting dielectric region and varies its own resistance as a function of the infrared radiation emitted by the flames.

A semiconductor device for flame detection, including: a semiconductor body having a first conductivity type conductivity, delimited by a front surface and forming a cathode region; an anode region having a second conductivity type conductivity, which extends within the semiconductor body, starting from the front surface, and forms, together with the cathode region, the junction of a photodiode that detect ultraviolet radiation emitted by the flames; a supporting dielectric region; and a sensitive region, which is arranged on the supporting dielectric region and varies its own resistance as a function of the infrared radiation emitted by the flames.

A solar cell manufacturing method including: forming, on one surface of a first conductivity-type semiconductor substrate, a first doped layer in which second conductivity-type impurities are diffused in a first concentration, and a second doped layer in which the second conductivity-type impurities are diffused in a second concentration lower than the first concentration, the second doped layer has surface roughness different from the first doped layer; and forming a metal electrode on the first doped layer to be electrically connected to the first doped layer, wherein a position of the first doped layer is detected based on a difference in light reflectance between the first and second doped layers, which results from a difference in surface roughness between the first and second doped layers, and then the metal electrode is formed in alignment with a detected position of the first doped layer.