Graphene Island/Silver Nanowire Hybrid Nanoelectrodes for High-Performance Terahertz Photomixers

A novel photomixer employing hybrid nanoelectrodes of silver nanowires (Ag-NWs, ϕ=120 nm) and graphene islands (GIs, 1 × 1µm²) demonstrates enhanced terahertz (THz) emission, achieving one-order-of-magnitude higher output power across 0.1-0.6 THz compared to conventional interdigitated designs. The hybrid nanoelectrodes were fabricated on low-temperature-grown GaAs via scalable transfer and lithography. The hybrid structure combines graphene's exceptional optical transparency and conductivity with Ag-NWs' plasmonic field enhancement and high current tolerance. Patterned GIs reduce photocarrier transport paths, enabling localized recombination and shorter carrier lifetimes, while the sparse Ag-NW network minimizes parasitic capacitance for extended bandwidth. This dual mechanism overcomes limitations in THz power and efficiency, highlighting the platform's potential for imaging, communications, and spectroscopy. Optimizing nanoelectrode geometry and interfacial coupling could further advance on-chip THz systems, bridging nanophotonics with practical optoelectronics.