A graphene hot hole transistor (PGBT), comprising - a layer stack including an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein - the layer stack further comprises an emitter barrier layer that is arranged between the base layer and the emitter layer, and a collector barrier layer that is arranged between the base and the collector layers and adjacent to the graphene layer, the collector barrier layer being arranged at an interface between the base layer and the collector layer, the collector barrier layer comprising a dielectric layer, wherein said dielectric layer is not compositionally graded, and a compositionally graded layer made of a dielectric material and arranged adjacent to the dielectric layer, the energy barrier for holes in said compositionally graded layer decreasing with increasing distance from the base layer towards the collector layer; - the layer stack is configured to allow a current of holes through the layer stack in a stacking direction pointing from the emitter layer through the base layer to the collector layer, under application of an input voltage that sets a base potential at the base layer below an emitter potential at the emitter layer and that sets a collector potential at the collector layer below the base potential, wherein an amount of said current of holes is controllable by an amount of a potential difference between the base potential and the emitter potential; - the emitter barrier layer is configured to block a hole transport between the emitter layer and the base layer under application of an input voltage between the base layer and the emitter layer having an amount below a threshold amount, and to allow holes passing the emitter barrier layer between the emitter and the base under an application of an input voltage between the base layer and the emitter layer above the threshold amount; - the emitter layer is made of a semiconductor material having p-type conductivity or of a metal having hole conductivity; and - the collector layer is made of a semiconductor material having a p-type conductivity or of a metal. - a layer stack including an emitter layer, a collector layer, and a base layer that comprises a graphene layer, wherein - the layer stack further comprises an emitter barrier layer that is arranged between the base layer and the emitter layer, and a collector barrier layer that is arranged between the base and the collector layers and adjacent to the graphene layer, the collector barrier layer being arranged at an interface between the base layer and the collector layer, the collector barrier layer comprising a dielectric layer, wherein said dielectric layer is not compositionally graded, and a compositionally graded layer made of a dielectric material and arranged adjacent to the dielectric layer, the energy barrier for holes in said compositionally graded layer decreasing with increasing distance from the base layer towards the collector layer; - the layer stack is configured to allow a current of holes through the layer stack in a stacking direction pointing from the emitter layer through the base layer to the collector layer, under application of an input voltage that sets a base potential at the base layer below an emitter potential at the emitter layer and that sets a collector potential at the collector layer below the base potential, wherein an amount of said current of holes is controllable by an amount of a potential difference between the base potential and the emitter potential; - the emitter barrier layer is configured to block a hole transport between the emitter layer and the base layer under application of an input voltage between the base layer and the emitter layer having an amount below a threshold amount, and to allow holes passing the emitter barrier layer between the emitter and the base under an application of an input voltage between the base layer and the emitter layer above the threshold amount; - the emitter layer is made of a semiconductor material having p-type conductivity or of a metal having hole conductivity; and - the collector layer is made of a semiconductor material having a p-type conductivity or of a metal.