A vacuum electron tube comprises at least one electron-emitting cathode and at least one anode arranged in a vacuum chamber, the cathode having a planar structure comprising a substrate comprising a conductive material, a plurality of nanotube or nanowire elements electrically insulated from the substrate, the longitudinal axis of the nanotube or nanowire elements substantially parallel to the plane of the substrate, and at least one first connector electrically linked to at least one nanotube or nanowire element so as to be able to apply a first electrical potential to the nanowire or nanotube element.

According to one embodiment, an electron emitting element includes a first region, a second region, and a third region. The first region includes a semiconductor including a first element of an n-type impurity. The second region includes diamond. The diamond includes a second element including at least one selected from the group consisting of nitrogen, phosphorous, arsenic, antimony, and bismuth. The third region is provided between the first region and the second region. The third region includes Al.sub.x1Ga.sub.1-x1N (0<x1≤1) including a third element including at least one selected from the group consisting of Si, Ge, Te and Sn. A +c-axis direction of the third region includes a component in a direction from the first region toward the second region.

Provided in the present disclosure is an electron emitting element 10 including a laminated structure in which a first electrode 1, an electron accelerating layer 6 made of an insulation film, a second electrode 3, and a cover film 7 are laminated in that order, in which the second electrode is an electrode which transmits electrons and emits electrons from a surface thereof, and the cover film is a film which transmits electrons, is a protective film made of a material different from that of the second electrode, and constitutes an electron emission surface 5.

Provided in the present disclosure is an electron emitting element 10 including a laminated structure in which a first electrode 1, an electron accelerating layer 6 made of an insulation film, a second electrode 3, and a cover film 7 are laminated in that order, in which the second electrode is an electrode which transmits electrons and emits electrons from a surface thereof, and the cover film is a film which transmits electrons, is a protective film made of a material different from that of the second electrode, and constitutes an electron emission surface 5.

According to one embodiment, an electron emitting element includes a first region, a second region, and a third region. The first region includes a semiconductor including a first element of an n-type impurity. The second region includes diamond. The diamond includes a second element including at least one selected from the group consisting of nitrogen, phosphorous, arsenic, antimony, and bismuth. The third region is provided between the first region and the second region. The third region includes Al.sub.x1Ga.sub.1-x1N (0<x1≤1) including a third element including at least one selected from the group consisting of Si, Ge, Te and Sn. A +c-axis direction of the third region includes a component in a direction from the first region toward the second region.

An article of manufacture includes a support structure including a cladding material and defining therein a plurality of substantially parallel cores. The article also includes a plurality of conically-shaped spikes protruding from a first side of the support structure. Each respective conically-shaped spike of the plurality of conically-shaped spikes includes a core material (i) extending through a corresponding core of the plurality of substantially parallel cores and (ii) comprising an axial protrusion that protrudes axially from the cladding material at the first side of the support structure. The axial protrusion of the core material is tapered to form the respective conically-shaped spike. The article also includes a refractory metal layer coating at least a portion of each respective conically-shaped spike and one or more electrodes connected to the refractory metal layer and configured to apply a voltage to the refractory metal layer.

An article of manufacture includes a support structure including a cladding material and defining therein a plurality of substantially parallel cores. The article also includes a plurality of conically-shaped spikes protruding from a first side of the support structure. Each respective conically-shaped spike of the plurality of conically-shaped spikes includes a core material (i) extending through a corresponding core of the plurality of substantially parallel cores and (ii) comprising an axial protrusion that protrudes axially from the cladding material at the first side of the support structure. The axial protrusion of the core material is tapered to form the respective conically-shaped spike. The article also includes a refractory metal layer coating at least a portion of each respective conically-shaped spike and one or more electrodes connected to the refractory metal layer and configured to apply a voltage to the refractory metal layer.

In an embodiment an ionization detector includes a gate-insulator-substrate electron-emission structure (GIS-EE) configured to emit low-energy electrons, a sample chamber configured for at least one gas to be detected, the sample chamber being adjacent to the GIS-EE and a measuring unit configured to detect and/or select charged particles, wherein the charged particles are due to the emitted electrons and/or comprise the emitted electrons.

In an embodiment an ionization detector includes a gate-insulator-substrate electron-emission structure (GIS-EE) configured to emit low-energy electrons, a sample chamber configured for at least one gas to be detected, the sample chamber being adjacent to the GIS-EE and a measuring unit configured to detect and/or select charged particles, wherein the charged particles are due to the emitted electrons and/or comprise the emitted electrons.

This electron emitting element includes a lower electrode, a surface electrode facing the lower electrode, a resistance layer arranged between the lower electrode and the surface electrode, and an insulating layer arranged between the lower electrode and the surface electrode. The resistance layer is an insulating resin layer containing conductive fine particles in a dispersed state. The insulating layer has a peripheral region for defining the electron emission region, and an emission control region which is arranged so as to overlap the electron emission region defined by the peripheral region. The emission control region is configured by a line-shaped insulating layer, a plurality of dot-shaped insulating layers, or both a line-shaped insulating layer and a plurality of dot-shaped insulating layers. The percentage of an area that the emission control region represents within an area of an electron emission region defined by the peripheral region is 2% or more and 60% or less.