Ultra-broadband graphene-InSb heterojunction photodetector

We demonstrate a room temperature ultra-broadband graphene-InSb heterostructure photodetector. By introducing a thin oxide layer between the P-type graphene film and N-type InSb, the dark current is suppressed sharply. The device can detect light from the visible to far infrared region, exhibiting a high responsivity of ∼70 mA W−1 at a typical wavelength of 1.7 μm. It is worth mentioning that the photodetector has delivered a mid-infrared (MIR) photoresponsivity of ∼42 mA W−1, which also opens a way for MIR communication technology.