Characteristics of vertically stacked graphene-layer infrared photodetectors

We evaluate the characteristics of the vertically stacked graphene-layer infrared photodetector (VS-GLIP). Each period of the stack (which constitutes the GLIP) consists of a GL (serving as a photosensitive element with a floating potential) sandwiched between barrier layers made of the van der Waals materials, and highly conducting emitter and collector contact n-GLs. The operation of VS-GLIPs is associated with the interband photoexcitation of electrons from the GLs (direct or followed by the tunneling), injection of the electrons from the emitter layer and the collection of both the photoexcited and injected electrons by the collector layer. At a small probability of the electron capture into the floating GLs, each GLIP section exhibits an elevated photoconductive gain. Due to the vertical multi-GLIP structure the absorption efficiency can be close to unity. Due to this and because the photocurrents produced by each GLIP in the stack are summarized, the VS-GLIP can exhibit elevated detector responsivity and detectivity, in particular, exceeding those of the GLIPs.