SPP waveguide of CdS nanowires and graphene nanobelts

Graphene has potential to replace germanium as compound semiconductor for high-performance devices because of its unique optoelectronic properties and availability of existing integrated circuit manufacturing technology. This study investigates surface plasmon polariton (SPP) waveguide-based interaction between CdS nanowires and graphene nanobelts to determine shortcomings of the existing technology. The structure uses MgF2 as cladding, which symmetrically covers CdS nanowires and graphene nanobelts. An air gap of same width is etched in middle of CdS nanowires and graphene nanobelts. SPP is optically excited. Gain compensation is obtained through coupling effect of nanowires, capacitance-enhanced effect of air gap and GaAs semiconductor material, and low refractive index of buffer layer to reduce transmission loss. The structure can achieve strong photon localization and easily implement low threshold for nanometer laser. Experiments on characteristics of SPP show that increasing air gap width of structure reduces transmission loss and increases limiting factors. Limiting factor of waveguide structure is less than 0.15, which indicates ultra-deep subwavelength constraints. SPP waveguide can be integrated with various nanophotonic and electronic devices and has broad application prospects in optical sensing, optical communication, and other fields.