Thales

Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Raphaël Aubry

Jean-Claude Jacquet

Sylvain Delage

Olivier Jardel

Stéphane Piotrowicz

Gaëlle Lehoucq

Marie-Antoinette Poisson

François Luc

José-Paolo Martins

Raphaël Guillemet

Julie Cholet

Mane-Si-Laure Lee Bouhours

Piero Gamarra

Anne Delboulbe

An optical element is provided, which is transparent at a wavelength of use λ, 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.

Optical transmission element, having a super-hydrophobic nanostructured surface having an anti-reflective property and covered with a compliant high-density thin film deposit

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 10cm, 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 10cmand 3.10cm.

Optimized buffer layer for high mobility field-effect transistor

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&#x3e;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.

Semiconductor device for electron emission in a vacuum

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Gometz le Chatel, France

Raphaël Aubry