Surface plasmon resonance bilayer graphene /Al2O3/GaAs Schottky junction near-infrared photodetector

In this paper, a bilayer graphene (BLG)/GaAs Schottky junction near-infrared (NIR) photodetector is investigated. The dark current is suppressed by inserting an Al2O3 passivation layer between the BLG and GaAs to prevent electron tunneling. In addition, a layer of Ag nanoparticles (NPs) is spin-coated on the surface of the BLG, which utilizes the plasma effect of the Ag NPs to enhance the local electric field, and promote the excitation and transport of the carriers in the BLG, thereby increasing photocurrent of the device. The combination of interface passivation and plasma effect has greatly improved the performance of BLG/GaAs Schottky junction NIR photodetector. Under the 808 nm incident light, the responsivity of the photodetector is 120 mA/W, which is 20 times higher than the traditional graphene/GaAs photodetector, the detection rate of the device can reach to 3.43 × 1011cm Hz1/2W−1 with the fast response/recovery time of 8.16 μs/98.43 μs. This high-performance BLG/GaAs Schottky junction can be widely used for the photo detection and solar cells fields.