Surface plasmon resonance enhanced self-powered graphene/Al2O3/InGaAs near-infrared photodetector

Abstract

In recent years, there has been extensive research on improving the performance of photodetectors. In this paper, the performance of a graphene/Al2O3/InGaAs photodetector is studied. In order to reduce the dark current of this device and improve the photocurrent, the structure of the device is optimized to improve the responsivity of the device. A 2 nm thick Al2O3 layer is inserted as the passivation layer. The InP layer between the SiNx layer and the InGaAs layer is retained. It is speculated that the InP layer could reduce the defects and interface states between layers. A layer of silver nanoparticles (Ag NPs) was spin coated on the surface of the single-layer graphene, and the surface plasmon resonance of Ag NPs could enhance the local electric field of InGaAs interface and increase the light absorption of graphene, which can promote carrier generation and transmission in graphene and, thus, effectively enhance the photocurrent of device. The improved device achieves a high responsivity of 265.41 mA/W at 1064 nm and a detection rate of 4.06 × 1011 cm Hz1/2 W−1. At −1.25 V, the responsivity of the device is improved to 1618.8 mA/W.