Abstract: In an optically controlled cold-cathode electron tube, the emitters 1, of nanometer and/or micron size and of elongate shape, have a structure comprising a first material (4) of sp2-bonding carbon type and a metallic second material (3), said first material being in contact with and surrounding said second material at its top and over the entire length of the emitter or at least part of said length starting from its top toward the base (b). The second material has a plasma frequency substantially equal to or greater than the frequency of the optical control wave.

Abstract: The invention relates to an optically-controlled field-emission cathode, comprising a substrate (10, 20, 30, 40, 50, 60, 70, 80, 90, 100) having at least one conducting surface (11, 21, 31, 41, 51, 61, 71, 81, 91, 101) and at least one conducting emitter element (16, 26, 36, 46, 56, 66, 76, 86, 96, 106) in the vicinity of a conducting surface, characterized in that it also comprises at least one photoconducting element (13, 23, 33, 43, 53, 63, 73, 83, 93, 103) electrically connected in series between at least one emitter element and a conducting surface of the substrate. Another subject of the invention is an amplifier tube comprising such a cathode. The application is for Vacuum tubes, in particular for microwave amplification, with a view for example to applications in telecommunications.

Abstract: In an optically controlled cold-cathode electron tube, the emitters 1, of nanometer and/or micron size and of elongate shape, have a structure comprising a first material (4) of sp2-bonding carbon type and a metallic second material (3), said first material being in contact with and surrounding said second material at its top and over the entire length of the emitter or at least part of said length starting from its top toward the base (b). The second material has a plasma frequency substantially equal to or greater than the frequency of the optical control wave.

Abstract: The invention relates to an optically-controlled field-emission cathode, comprising a substrate (10, 20, 30, 40, 50, 60, 70, 80, 90, 100) having at least one conducting surface (11, 21, 31, 41, 51, 61, 71, 81, 91, 101) and at least one conducting emitter element (16, 26, 36, 46, 56, 66, 76, 86, 96, 106) in the vicinity of a conducting surface, characterized in that it also comprises at least one photoconducting element (13, 23, 33, 43, 53, 63, 73, 83, 93, 103) electrically connected in series between at least one emitter element and a conducting surface of the substrate. Another subject of the invention is an amplifier tube comprising such a cathode. The application is for Vacuum tubes, in particular for microwave amplification, with a view for example to applications in telecommunications.

Abstract: A microwave modulable field-effect cathode which includes at least one array of emissive tips. A microwave modulation signal is produced by a device including a microwave-controllable semiconductor modulation element which is close to the tip array, and a short microline for conveying the modulation signal to the tip array. The microline provides impedance matching between the tip array and the semiconductor modulation element. Such a device can find application as a compact field-effect cathode, as one example.

Abstract: The invention relates to the "hardening" (resistance to ionizing radiations) of MOS-type components. In order to avoid the effects of these radiations (creation of electron-hole pairs), there is deposited on a substrate (1) of monocrystalline Si a layer of YSZ (2), and then a thin layer of monocrystalline Si (3). The other steps of production of the components are the same as conventional.

Abstract: Disclosed is a method for the fabrication of field emission peaks using a monocrystalline substrate with a suitable orientation coated with an insulating layer where square-shaped elementary zones with a suitable orientation with respect to the substrate have been removed. Silicon is deposited by selective epitaxy in these zones. The epitaxial growth of silicon, at high speed parallel to the substrate and at low speed along faces of the substrate at 45.degree. to the substrate, enables the making of pyramidal peaks which, afater being coated with tungsten, form emitting peaks.

Abstract: Disclosed is a device made of superconductive material wherein the superconducting layer is enclosed by at least one material which is a conductor of ions of one of the anionic constituent elements of the superconductive layer. This makes it possible to adjust the stoichiometry of the superconductive layer. The disclosure also concerns a method for adjusting the content of the constituent elements of the superconductive layer by electrolysis.

Abstract: The invention provides a process comprising a step for depositing at least one intrinsic or doped monocrystalline silicon layer on a substrate, also monocrystalline, followed by a step for forming a thin silica layer at the level of the original substrate-silicon interface. The silica layer is obtained by oxidation through the substrate, followed by a heat treatment step during which the monocrystalline silicon is oxidized by the implanted oxygen ions. The first approach may take place according to two variants: thermal or plasma oxidation of the silicon-substrate interface. Oxidation takes place during the return to ambient temperature of the stack of layers after the deposit has been made.