Abstract: An optical element is provided, which is transparent at a wavelength of use ?, and which has a super-hydrophobic nanostructured surface that has an anti-reflection property, the surface having an array of pads. —The pads have a nanoscale width, a height h, an aspect ratio of less than 1/2, and the pitch p of the array is such that p<h and the element comprises a top layer of thickness less than h/5 which covers without discontinuity and conformally the nanostructured surface, the top layer being obtained via a step of annealing at a temperature comprised between 500° C. and 1200° C. and being in a material of a hardness greater than the hardness of the material of said nanostructured surface.

Abstract: The optoelectronic device includes a matrix of optoelectronic components including semiconductor optical amplifiers SOAs, the semiconductor optical amplifiers SOAs containing an active layer of gallium nitride GaN having multiple InGaN/GaAsN or InGaN/AlGaN quantum wells on a substrate of p-doped gallium nitride and covered with a layer of n-doped gallium nitride. The p-doped gallium nitride GaN substrate forms a column of p-GaN covered with a layer of an insulator in biocompatible material. The device can include a matrix having multiple electronic components of different heights. The optoelectronic component can be a photodiode or a semiconductor optical amplifier SOA. This optoelectronic device can be used in epiretinal or subretinal prostheses. A single epiretinal or subretinal prosthesis can include a matrix of photodiodes and a matrix of semiconductor optical amplifiers SOAs.

Abstract: The optoelectronic device includes a matrix of optoelectronic components including semiconductor optical amplifiers SOAs, the semiconductor optical amplifiers SOAs containing an active layer of gallium nitride GaN having multiple InGaN/GaAsN or InGaN/AlGaN quantum wells on a substrate of p-doped gallium nitride and covered with a layer of n-doped gallium nitride. The p-doped gallium nitride GaN substrate forms a column of p-GaN covered with a layer of an insulator in biocompatible material. The device can include a matrix having multiple electronic components of different heights. The optoelectronic component can be a photodiode or a semiconductor optical amplifier SOA. This optoelectronic device can be used in epiretinal or subretinal prostheses. A single epiretinal or subretinal prosthesis can include a matrix of photodiodes and a matrix of semiconductor optical amplifiers SOAs.

Abstract: A stack along a z-axis for a high-electron-mobility field-effect transistor, comprises: a buffer layer comprising a first semiconductor material comprising a binary, ternary or quaternary nitride compound having a first bandgap, a barrier layer comprising a second semiconductor material comprising a binary, ternary or quaternary nitride compound and having a second bandgap, the second bandgap wider than the first bandgap, a heterojunction between the buffer and barrier layers and, a two-dimensional electron gas located in an XY plane perpendicular to the z-axis and in the vicinity of the heterojunction wherein: the buffer layer comprises a zone comprising fixed negative charges of density per unit volume higher than or equal to 1017 cm?3, the zone having a thickness smaller than or equal to 200 nm, the product of multiplication of the density per unit volume of fixed negative charges by the thickness of the zone between 1012 cm?2 and 3.1013 cm?2.

Abstract: The optoelectronic device includes a matrix of optoelectronic components including semiconductor optical amplifiers SOAs, the semiconductor optical amplifiers SOAs containing an active layer of gallium nitride GaN having multiple InGaN/GaAsN or InGaN/AlGaN quantum wells on a substrate of p-doped gallium nitride and covered with a layer of n-doped gallium nitride. The p-doped gallium nitride GaN substrate forms a column of p-GaN covered with a layer of an insulator in biocompatible material. The device can include a matrix having multiple electronic components of different heights. The optoelectronic component can be a photodiode or a semiconductor optical amplifier SOA. This optoelectronic device can be used in epiretinal or subretinal prostheses. A single epiretinal or subretinal prosthesis can include a matrix of photodiodes and a matrix of semiconductor optical amplifiers SOAs.

Abstract: A field-effect transistor comprising a stack of semiconductor materials, the upper face of the stack being covered with a passivation layer comprises two sub-layers: a first sub-layer extending over a second zone of low intensity comprising a first material with electric breakdown field Ecl1, the charge of the first sub-layer being strictly less than the charge of the upper face of the stack, a second sub-layer extending over a first zone of high intensity and covering the first sub-layer, the second sub-layer comprising a second material with electrical breakdown field Ecl2 strictly greater than Ecl1.

Abstract: A stack along a z-axis for a high-electron-mobility field-effect transistor, comprises: a buffer layer comprising a first semiconductor material comprising a binary, ternary or quaternary nitride compound having a first bandgap, a barrier layer comprising a second semiconductor material comprising a binary, ternary or quaternary nitride compound and having a second bandgap, the second bandgap wider than the first bandgap, a heterojunction between the buffer and barrier layers and, a two-dimensional electron gas located in an XY plane perpendicular to the z-axis and in the vicinity of the heterojunction wherein: the buffer layer comprises a zone comprising fixed negative charges of density per unit volume higher than or equal to 1017 cm?3, the zone having a thickness smaller than or equal to 200 nm, the product of multiplication of the density per unit volume of fixed negative charges by the thickness of the zone between 1012 cm?2 and 3.1013 cm?2.

Abstract: A semiconductor device for electron emission in a vacuum comprises a stack of two or more semi-conductor layers of N and P type according to sequence N/(P)/N forming a juxtaposition of two head-to-tail NP junctions, in materials belonging to the III-N family, two adjacent layers forming an interface. The semiconductor materials of the layers of the stack close to the vacuum, where the electrons reach a high energy, have a band gap Eg>c/2, where c is the electron affinity of the semiconductor material, the P-type semiconductor layer being obtained partially or completely, by doping impurities of acceptor type or by piezoelectric effect to exhibit a negative fixed charge in any interface between the layers, a positive bias potential applied to the stack supplying, to a fraction of electrons circulating in the stack, the energy needed for emission in the vacuum by an emissive zone of an output layer.

Abstract: A semiconductor device for electron emission in a vacuum comprises a stack of two or more semi-conductor layers of N and P type according to sequence N/(P)/N forming a juxtaposition of two head-to-tail NP junctions, in materials belonging to the III-N family, two adjacent layers forming an interface. The semiconductor materials of the layers of the stack close to the vacuum, where the electrons reach a high energy, have a band gap Eg>c/2, where c is the electron affinity of the semiconductor material, the P-type semiconductor layer being obtained partially or completely, by doping impurities of acceptor type or by piezoelectric effect to exhibit a negative fixed charge in any interface between the layers, a positive bias potential applied to the stack supplying, to a fraction of electrons circulating in the stack, the energy needed for emission in the vacuum by an emissive zone of an output layer.