High-Speed and High-Sensitivity SWCNTs/Graphene/Si Photodetector Enhanced by Ag NPs for Optical Communication

This article presents Ag nanoparticles (NPs)/single-walled carbon nanotubes (SWCNTs)/ Graphene/Si photodetector (PD) operating in the near-infrared (NIR) region. The metal NPs are combined on the prepared PD to improve performance through the local surface plasmon resonance (LSPR) effect. Meanwhile, the speed of the device is improved by the high mobility of SWCNTs. Moreover, monolayer graphene improves the contact between SWCNTs and Si, which further promotes the speed of the device. At −1 V, the responsivity of PD is 276 mA/W for the 808 nm laser and 493 mA/W for the 1064 nm laser. The detectivity of this PD reaches $1.60\times 10^{{11}}$ Jones at 808 nm and $2.87\times 10^{{11}}$ Jones at 1064 nm. It also has a good response time under 1064 nm illumination, with the rise time of 2.33 $\mu $ s and the fall time of 16.0 $\mu $ s. Due to its good performance, it can be practically applied in optical communication systems to achieve signal transmission through optoelectronic conversion. Such Ag NPs/SWCNTs/Graphene/Si heterostructured PDs with high performance and high speed can be widely used for NIR photodetection.