Feasibility of Integrating Bimetallic Au-Ag Non-Alloys Nanoparticles Embedded in Reduced Graphene Oxide Photodetector

Abstract

To coordinate the resonant wavelength of the plasmonic nanoparticles (NPs), the emission band of the reduced graphene oxide (rGO) photodetector at the NIR-region is crucial for the optimal plasmon-enhanced luminescence in the device. In contrast to monometallic NPs, where limits the dimensions and extended resonant wavelength, we integrated an Au-Ag bimetallic NPs (BMNPs) to enable resonance tuning at the longer wavelength at the excitation source of 785 nm. These features showed an increase in radiative recombination rates as well as the quantum yield efficiency of the device. The BMNPs were produced from the dewetting process of 600 °C and 500 °C, both at 1 min after the deposition thickness layer of Au (8 nm) and Ag (10 nm) on the Si substrate using the electron-beam evaporation process. Our BMNPs-rGO photodetector exhibited the responsivity of 2.25 · A W−1, Jones of specific detectivity of 2.45×1011Jones, and external quantum efficiency (EQE) of 356%. The rise time and fall time for the photodetector were 32 ns and 186 ns, respectively. This work provided an essential information to enable the versatile plasmon-enhanced application in 2-dimensional (2D) material optoelectronic devices.