Ag NPs and MoS2 QDs double modified graphene/GaAs near-infrared photodetector

Abstract

The light absorption enhancement ability of quantum dots (QDs) and the localized surface plasmon resonance (LSPR) effect of metal nanoparticles (NPs) can effectively improve the performance of photodetectors. In this paper, an Ag NPs and MoS2 QDs double modified graphene/GaAs near-infrared photodetector is investigated. The performance of the detector is improved by adopting the LSPR effect of Ag NPs and the dielectric confinement effect of MoS2 QDs. After subsequent testing and analysis, the photodetector responsivity is 21.1 mA W−1 and the detectivity is 8.4 × 1012 cm Hz1/2 W−1 at 808 nm wavelength; the responsivity and detectivity at 1064 nm wavelength can be up to 18.4 mA W−1 and 3.39 × 1012 cm Hz1/2 W−1, respectively. At the same time, under a 4 kHz pulsed illumination, the rise time and fall time are 15.87 μs and 89.95 μs respectively. Compared with previous devices, the new device has lower dark current and higher detectivity while having good responsivity and response time.