Abstract: A method for producing a nanotip from a tip material provides a substrate which consists of the tip material or has the material in the form of a coating, produces a mask from a mask material selected so that, in a predefined reactive ion etching process, the mask material is removed at a lower etching rate than the tip material, and carries out the reactive ion etching process in an etching chamber. The mask material is additionally selected so that a gaseous component is released therefrom during the reactive ion etching process, the gaseous component not being released from the tip material. The method further comprises detecting the gaseous component while the ion etching process is being carried out, repeatedly determining whether an amount of the gaseous component in the etching chamber reaches a predefined lower threshold, and stopping the reactive ion etching process when the lower threshold is reached.

Abstract: A graphene base transistor comprises on a semiconductor substrate surface an emitter pillar and an emitter-contact pillar, which extend from a pillar foundation in a vertical direction. A dielectric filling layer laterally embeds the emitter pillar and the emitter-contact pillar above the pillar foundation. The dielectric filling layer has an upper surface that is flush with a top surface of the emitter pillar and with the at least one base-contact arm of a base-contact structure. A graphene base forms a contiguous layer between a top surface of the emitter pillar and a top surface of the base-contact arm. A collector stack and the base have the same lateral extension parallel to the substrate surface and perpendicular to those edges of the top surface of the emitter pillar and the base-contact arm that face each other.

Abstract: A method for producing a nanotip from a tip material provides a substrate which consists of the tip material or has the material in the form of a coating, produces a mask from a mask material selected so that, in a predefined reactive ion etching process, the mask material is removed at a lower etching rate than the tip material, and carries out the reactive ion etching process in an etching chamber. The mask material is additionally selected so that a gaseous component is released therefrom during the reactive ion etching process, the gaseous component not being released from the tip material. The method further comprises detecting the gaseous component while the ion etching process is being carried out, repeatedly determining whether an amount of the gaseous component in the etching chamber reaches a predefined lower threshold, and stopping the reactive ion etching process when the lower threshold is reached.

Abstract: A graphene base transistor comprises on a semiconductor substrate surface an emitter pillar and an emitter-contact pillar, which extend from a pillar foundation in a vertical direction. A dielectric filling layer laterally embeds the emitter pillar and the emitter-contact pillar above the pillar foundation. The dielectric filling layer has an upper surface that is flush with a top surface of the emitter pillar and with the at least one base-contact arm of a base-contact structure. A graphene base forms a contiguous layer between a top surface of the emitter pillar and a top surface of the base-contact arm. A collector stack and the base have the same lateral extension parallel to the substrate surface and perpendicular to those edges of the top surface of the emitter pillar and the base-contact arm that face each other.

Abstract: A junction transistor, comprising, on a substrate an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein an emitter barrier layer is arranged between the base layer and the emitter layer, and a collector barrier layer is arranged between the base and the collector layers and adjacent to the graphene layer, characterized in that the collector barrier layer is a compositionally graded material layer, which has an electron affinity that decreases in a direction pointing from the base layer to the collector layer.

Abstract: A depletion-layer transistor comprising a base, an emitter and a collector, in which the emitter contains a tunnel diode which permits a tunnel current of charge carriers from the emitter in the direction of the collector when an emitter-base voltage above a first threshold voltage is applied in the direction of current flow, and in which the base contains a graphene layer.

Abstract: A hot hole transistor with a graphene base comprises on a substrate an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein an emitter barrier layer is arranged between the base layer and the emitter layer, and a collector barrier layer is arranged between the base and the collector layers and adjacent to the graphene layer.

Abstract: A hot hole transistor with a graphene base comprises on a substrate an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein an emitter barrier layer is arranged between the base layer and the emitter layer, and a collector barrier layer is arranged between the base and the collector layers and adjacent to the graphene layer.

Abstract: A junction transistor, comprising, on a substrate an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein an emitter barrier layer is arranged between the base layer and the emitter layer, and a collector barrier layer is arranged between the base and the collector layers and adjacent to the graphene layer, characterized in that the collector barrier layer is a compositionally graded material layer, which has an electron affinity that decreases in a direction pointing from the base layer to the collector layer.

Abstract: A depletion-layer transistor comprising a base, an emitter and a collector, in which the emitter contains a tunnel diode which permits a tunnel current of charge carriers from the emitter in the direction of the collector when an emitter-base voltage above a first threshold voltage is applied in the direction of current flow, and in which the base contains a graphene layer.