Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas at a concentration of about 8 to 13 percent to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a first layer of carbon-based material to a thickness greater than about 0.5 micrometers, subsequently reducing the concentration of the carbon-containing gas and continuing to grow a second layer of carbon-based material, the second layer being much thicker than the first layer. The substrate is subsequently removed from the first layer and an electrode is applied to the second layer. The surface of the substrate may be patterned before growth of the first layer to produce a patterned surface on the field emission device. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes.

Abstract: A cap can comprise an aperture, and an attenuator may block the aperture during at least one point in time. In one embodiment, the attenuator can include a cover that may be displaced by a spring. In another embodiment, an electron gun, such as an electron gun, may comprise a support cap with an aperture, a displaceable cover that may cover the aperture, and a spring. A material attached to the spring and acting as a fuse may release the spring and expose the aperture after an electrical current blows the “fuse.” In yet another embodiment, a method for using a tube may comprise evacuating the tube while a cover covers an aperture in the support cap of a electron gun that is at least partially in the tube and moving the cover to expose the aperture after the tube is sealed.

Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a carbon-based body to a thickness greater than 20 micrometers, subsequently removing the substrate and then applying an electrical contact to one surface of the body. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes. The surface of the substrate may be patterned before growth of the carbon-based body to produce a patterned surface on the field emission device after the substrate is removed.

Abstract: A field emission cathode providing for dynamic adjustment of beam shape is disclosed. Beam shape adjustment is accomplished by segmenting the gate electrode of a gated field emission cathode and independently driving the various gate segments to form the desired beam shape. Segments can be turned on and off as the beam is deflected allowing dynamic correction of aberrations in the beam. A focus lens can be placed on the gated cathode to produce a parallel electron beam. In addition, a hollow cathode can be produced to minimize space charge repulsion in a beam.

Abstract: Apparatus and method for mounting a field emission device having emitters and an extraction grid in an electron gun are provided. The apparatus may be adapted from parts of a conventional electron gun that uses a thermionic emitter. Electrical connection to the grid is provided by bumps that are spring-loaded against a conducting surface, such as the second grid of a conventional electron gun.

Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas at a concentration of about 8 to 13 percent to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a first layer of carbon-based material to a thickness greater than about 0.5 micrometers, subsequently reducing the concentration of the carbon-containing gas and continuing to grow a second layer of carbon-based material, the second layer being much thicker than the first layer. The substrate is subsequently removed from the first layer and an electrode is applied to the second layer. The surface of the substrate may be patterned before growth of the first layer to produce a patterned surface on the field emission device. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes.

Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas at a concentration of about 8 to 13 per cent to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a first layer of carbon-based material to a thickness greater than about 0.5 micrometers, subsequently reducing the concentration of the carbon-containing gas and continuing to grow a second layer of carbon-based material, the second layer being much thicker than the first layer. The substrate is subsequently removed from the first layer and an electrode is applied to the second layer. The surface of the substrate may be patterned before growth of the first layer to produce a patterned surface on the field emission device. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes.

Abstract: A source of a focused electron beam is provided for use in a cathode ray tube (CRT) or vacuum microelectronic device. A carbon-based field emission cathode, extraction gate and focus lens are formed as an integrated structure using fabrication techniques that are used to form integrated circuits. An external focus lens is used to confine the beamlets from a large number of carbon-based surfaces. A convergence cup accelerates the beam toward a drift space and finally to a screen on a CRT or other device. The source may be much more compact than present CRT electron optics apparatus.

Abstract: An electron field emission device is provided by placing a substrate in a reactor, heating the substrate and supplying a mixture of hydrogen and a carbon-containing gas at a concentration of about 8 to 13 per cent to the reactor while supplying energy to the mixture of gases near the substrate for a time to grow a first layer of carbon-based material to a thickness greater than about 0.5 micrometers, subsequently reducing the concentration of the carbon-containing gas and continuing to grow a second layer of carbon-based material, the second layer being much thicker than the first layer. The substrate is subsequently removed from the first layer and an electrode is applied to the second layer. The device is free-standing and can be used as a cold cathode in a variety of electronic devices such as cathode ray tubes, amplifiers and traveling wave tubes. The surface of the substrate may be patterned before growth of the first layer to produce a patterned surface on the field emission device.

Abstract: Method is provided for controlling the concentration of a dopant introduced into an epitaxial film during CVD or sublimation growth by controlling the energy of dopant atoms impinging on the film in a supersonic beam. Precursor materials may also be introduced by supersonic beam. Energy of the dopant atoms may be changed by changing flow conditions in the supersonic beam or changing carrier gases. Flow may be continuous or pulsed. Examples of silicon carbide doping are provided.