Detection Properties of Ge MSM Photodetector Enhanced by Au Nanoparticles

A high-performance near-infrared (NIR) hybrid MSM Ge photodetector is proposed in this work, and the properties of this device can be significantly enhanced by the hybrid structure consisting of Ge nanopillar arrays and Au nanoparticles (Au NPs). The responsivity of this hybrid device at 1550 nm could reach 0.572 A/W, which is 4.17 times larger than that of the planar Ge photodetector. The responsivity enhancement is related to the light trapping effect of nanopillar arrays, the electrostatic effect, and the Fermi pinning effect. The light trapping effect of nanopillar arrays can effectively improve the absorption of the Ge photodetector, while the electrostatic effect enhances the spatial electron–hole separation and suppresses the recombination rate. Moreover, the Fermi pinning effect can lower the Schottky barrier of Au/Ge interface. Our results showed a new light on the high-performance Ge photodetector by hybridization of nanopillar arrays and Au NPs. The presented hybrid Ge photodetector will have great potential for application in innovative optoelectronic devices, particularly as a high-performance NIR photodetector for optical communication.