A vacuum channel field effect transistor includes a first insulator on a p-type semiconductor substrate, a gate electrode on the first insulator, a second insulator on the gate electrode, a drain electrode on the second insulator, and an n+ impurity diffusion layer in the surface of the p-type semiconductor substrate, the n+ impurity diffusion layer being in contact with a side wall including side faces of the first insulator, the gate electrode, and the second insulator. Application of predetermined voltages to the n+ impurity diffusion layer, the gate electrode, and the drain electrode causes charge carriers in the n+ impurity diffusion layer to travel through a vacuum or air faced by the side wall to the drain electrode, which can increase the source-drain current.

A vacuum channel field effect transistor includes a first insulator on a p-type semiconductor substrate, a gate electrode on the first insulator, a second insulator on the gate electrode, a drain electrode on the second insulator, and an n+ impurity diffusion layer in the surface of the p-type semiconductor substrate, the n+ impurity diffusion layer being in contact with a side wall including side faces of the first insulator, the gate electrode, and the second insulator. Application of predetermined voltages to the n+ impurity diffusion layer, the gate electrode, and the drain electrode causes charge carriers in the n+ impurity diffusion layer to travel through a vacuum or air faced by the side wall to the drain electrode, which can increase the source-drain current.

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.

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.

A laminated body is provided in a circumferential shape with a gap formed in a part of a circumferential direction on a semiconductor layer. In the laminated body, a first insulating layer, a gate layer, a second insulating layer, and a drain layer are layered in this order from the semiconductor layer side. An impurity diffusion layer is formed on a surface of the semiconductor layer, and a backside electrode on a backside surface. The impurity diffusion layer extends from a position in contact with side walls in a channel space to an outside of the laminated body through a region corresponding to the gap on the surface of the semiconductor layer. A portion of the impurity diffusion layer beyond the laminated body is a contact region to which a wiring for applying a predetermined voltage is connected. A cover layer made of an insulating material is formed in an upper portion and a periphery of the annular portion including the laminated body and the gap.

A vacuum channel field effect transistor includes a first insulator on a p-type semiconductor substrate, a gate electrode on the first insulator, a second insulator on the gate electrode, a drain electrode on the second insulator, and an n+ impurity diffusion layer in the surface of the p-type semiconductor substrate, the n+ impurity diffusion layer being in contact with a side wall including side faces of the first insulator, the gate electrode, and the second insulator. Application of predetermined voltages to the n+ impurity diffusion layer, the gate electrode, and the drain electrode causes charge carriers in the n+ impurity diffusion layer to travel through a vacuum or air faced by the side wall to the drain electrode, which can increase the source-drain current.

A vacuum channel field effect transistor includes a first insulator on a p-type semiconductor substrate, a gate electrode on the first insulator, a second insulator on the gate electrode, a drain electrode on the second insulator, and an n+ impurity diffusion layer in the surface of the p-type semiconductor substrate, the n+ impurity diffusion layer being in contact with a side wall including side faces of the first insulator, the gate electrode, and the second insulator. Application of predetermined voltages to the n+ impurity diffusion layer, the gate electrode, and the drain electrode causes charge carriers in the n+ impurity diffusion layer to travel through a vacuum or air faced by the side wall to the drain electrode, which can increase the source-drain current.

Improved ultraviolet field-emission lamps can be safely deployed close to people because they eliminate the use of toxic materials, mitigate heating issues, and emit light in a wavelength range that is safe for human exposure.

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.

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.