Abstract:
An image intensifier or converter is described comprising an array of JFETs having separate gates which when pulsed block the channel of the associated JFET. Each JFET is connected in series with a display element, such as an electroluminescent diode. Incident imaging photons absorbed in the channel regions unblock the associated FET causing radiation emission from the associated display element.
Abstract:
A photoemitter of improved quantum efficiency is formed by smoke or low density deposition of photoemissive materials on a substrate. Significantly, the photoemissive layer is deposited in the presence of a low pressure gas to form a layer whose density is not greater than 20% and preferably not greater than 5% of the photoemissive material in its bulk form. Individual particle size is controlled and deposited particles are isolated, affording greater surface contact area with the subsequently deposited constituent materials of the photoemissive surface, thereby enhancing interaction and increasing the photoelectron emission. The low density, randomly oriented smoke deposits provide a photosensitive surface characterized by high absorption, low reflective losses, and low transmissive losses. The spectral response curve of smoke photoemitters peaks further into the red or near infrared region than prior art devices, rendering the smoke photoemitters of the invention ideally suited for use as near infrared sensors in low light level imaging system.
Abstract:
A transmissive semiconductor photocathode structure comprising a first monocrystalline epitaxial layer of silicon or germanium about 200 to 300 nanometers thick on a major surface of a transparent monocrystalline dielectric substrate. On the silicon or germanium layer is a second monocrystalline epitaxial layer of a III-V or II-VI semiconductor compound having a thickness of at least about three microns. On the second layer is a third monocrystalline epitaxial layer of a III-V semiconductor compound having an energy bandgap smaller than the second layer compound and having a thickness on the order of from about one micron to about five microns. Also disclosed is a photoemissive electron tube utilizing the transmissive photocathode structure, with a work function reducing material deposited on the emissive surface of the third layer.
Abstract:
Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for H2 production from water splitting half-reaction.
Abstract:
An electron gun that generate an electron flow and the application of this gun to produce rf energy or for injectors. The electron gun includes an electrostatic cavity having a first stage with emitting faces and multiple stages with emitting sections. The gun also includes a mechanism for producing an electrostatic force which encompasses the emitting faces and the multiple emitting sections so electrons are directed from the emitting faces toward the emitting sections to contact the emitting sections and generate additional electrons and to further contact other emitting sections to generate additional electrons and so on then finally to escape the end of the cavity. A method for producing a flow of electrons.
Abstract:
A photocathode device for use in an image intensifier, fabricated with a photoemissive semiconductor wafer having an active cathode layer which includes a central region of a first predetermined height surrounded by a peripheral region of a second predetermined height. The first predetermined height of the central region is configured to be greater than the second predetermined height of the peripheral region in order to create a recessed contact structure which is less likely to have unwanted emission points. A layer of conductive material covers the peripheral region to provide an electrical contact to the photocathode device. A layer of insulating material covers the layer of conductive material in order to protect the contact layer from being damage during handling operations.
Abstract:
An improved photocathode and image intensifier tube are disclosed along with a method for making both the tube and photocathode. The disclosed photocathode and image intensifier tube have an active layer comprising two or more sublayers. The first sublayer has a first concentration of a group III-V semiconductor compound while the second sublayer has a second concentration of the group III-V semiconductor compound. The multilayer active layer is coupled to a window layer.
Abstract:
The invention is directed to continuous dynodes formed by thin-film processing techniques. According to one embodiment of the invention, a continuous dynode is formed by reacting a chemical vapor in the presence of a substrate at a temperature and pressure sufficient to result in chemical vapor deposition. In another embodiment, the layer is formed by liquid phase deposition and in another embodiment, the layer is formed by nitriding or oxidizing a substrate.