Multi-band enhanced graphene photodetector based on localized surface plasmon

In this paper, a graphene photodetector modified with both gold nanoparticles and silver nanoparticles was discussed. The performance of the photodetector was improved by the common electrode structure prepared by transferring graphene on the top of the device. The gold nanoparticles and silver nanoparticles prepared via the annealing process can excite localized surface plasmon under illumination, and the photoresponse of the photodetector in the wavelength range of 400−470 nm and 510−620 nm. The responsivity increased by up to 2.8 times. As the photosensitive material, graphene on the top participated in photoelectric response, improving the performance of the photodetector in the wavelength range of 400−850 nm, and realized 1.4–1.5 times performance improvement in the wide-band range. Through the above improvements, the responsivity of the photodetector under 400−470 nm and 510−620 nm illumination increased by 2–4 times; the specific detectivity under 450 nm illumination increased by 2.7 times, and the external quantum efficiency increased by 400 %. Therefore, the photodetector can achieve enhancement in its multi-band selective response and improvement in its optical detection performance in a wide-band range.