Graphene charge-injection photodetectors

Charge-coupled devices are widely used imaging technologies. However, their speed is limited due to the complex readout process, which involves sequential charge transfer between wells, and their spectral bandwidth is limited due to the absorption limitations of silicon. Here we report graphene charge-injection photodetectors. The devices have a deep-depletion silicon well for charge integration, single-layer graphene for non-destructive direct readout and multilayer graphene for infrared photocharge injection. The photodetectors offer broadband imaging from ultraviolet (around 375 nm) to mid-infrared (around 3.8 μm), a conversion gain of 700 pA per electron, a responsivity above 0.1 A W −1 in the infrared region and a fast response time under 1 μs.